15-20 points will be added.
Make a Paper about photosynthesis with the following guide questions
1. Define photosynthesis
2. Explain how Photosynthesis works. (the simpler the better)
3. Discuss the importance of photosynthesis.
Instructions:
1. To be done strictly in groups of five maximum.
2. Write it in short bond paper with 1 inch margins all through out, Times New Roman font, font size 12. Justified paragraphs.
3. Names of the group members to be written at the last page lower left corner.
4. Use proper APA style citation in text and without.
5. Must have at least 5 citations. At least 1 book citation no later than 1990.
6. Deadline must be on or before September 8, 2010 5PM.
You may pass the paper during class or at the Biology faculty room at R401 (del Roasrio Hall).
I will rigorously check your work. If I see sections copied directly from other people's work or copied directly from a source without citation. It will be an automatic zero and no points will be added.
Expect a quiz from your work.
Pls check on the comments below for additional instructions.
Monday, August 30, 2010
Midterm Exam
The Midterm exam is pure identification and draw and labelling of various images seen and discussed in the Lectures and on the website.
Tuesday, August 24, 2010
Supplement - Stem
Different types of stems: axis of a plant.
Stolon: running stems, which trail above the ground.
Tuber: subterranean swellings of plant axes.
Volubilate twining: a stem that will wind around objects for support.
Section of a bulb: division of a bulb that allows study of the interior.
Bulb: plant organ that allows for the growth of the plant every year.
Rhizome: stem that annually produces adventitious roots.
*note some items in the exam may be taken from the supplements posted
Stolon: running stems, which trail above the ground.
Tuber: subterranean swellings of plant axes.
Volubilate twining: a stem that will wind around objects for support.
Section of a bulb: division of a bulb that allows study of the interior.
Bulb: plant organ that allows for the growth of the plant every year.
Rhizome: stem that annually produces adventitious roots.
*note some items in the exam may be taken from the supplements posted
Supplement - Leaves
Different types of leaves
A typical leaf of a dicotyledonous plant consists of two main parts :
• the blade
• the petiole
The blade is thin and expanded and is supported by a network of veins while the petiole is slender and connects the leaf to the stem.
The leaf blade
The leaf blade varies greatly in shape and there are numerous terms to describe its general shape. These terms describe the leaf's general shape, apex, base, margin, and veins
general shape apex base margin veins
The leaf blade has two types of configuration. It may be in one unit, in which case the leaf is called a simple leaf, or it may be divided into numerous small parts that look like individual leaves and which form a compound leaf. It may be difficult to tell whether one is looking at a simple leaf or the leaflet (pinna) of a compound leaf. The distinction can be made by the fact that a leaf (simple or compound) has an axial bud between the petiole and the stem.
The petiole
The petiole of a leaf may vary considerably and can be long, short, rounded or flat. Some leaves have no petioles in which case they are said to be sessile. At the base of the petiole in many leaves are small leaf-like structures called stipules e.g. in peas, beans and roses. Between the petiole and the stem is a bud of a potential branch (an axial bud).
Leaves may be arranged on the stem in a variety of ways. The place on the stem from where the leaves grow is called a node and the part between the nodes is the internode. If only one leaf arises at a node the leaves are said to be alternate, if there are two leaves they are opposite and if there are more than two they are whorled.
*note some items in the exam may be taken from the supplements posted
The dicotyledonous leaf
A typical leaf of a dicotyledonous plant consists of two main parts :
• the blade
• the petiole
The blade is thin and expanded and is supported by a network of veins while the petiole is slender and connects the leaf to the stem.
The leaf blade varies greatly in shape and there are numerous terms to describe its general shape. These terms describe the leaf's general shape, apex, base, margin, and veins
general shape apex base margin veins
The leaf blade has two types of configuration. It may be in one unit, in which case the leaf is called a simple leaf, or it may be divided into numerous small parts that look like individual leaves and which form a compound leaf. It may be difficult to tell whether one is looking at a simple leaf or the leaflet (pinna) of a compound leaf. The distinction can be made by the fact that a leaf (simple or compound) has an axial bud between the petiole and the stem.
The petiole
The petiole of a leaf may vary considerably and can be long, short, rounded or flat. Some leaves have no petioles in which case they are said to be sessile. At the base of the petiole in many leaves are small leaf-like structures called stipules e.g. in peas, beans and roses. Between the petiole and the stem is a bud of a potential branch (an axial bud).
Leaves may be arranged on the stem in a variety of ways. The place on the stem from where the leaves grow is called a node and the part between the nodes is the internode. If only one leaf arises at a node the leaves are said to be alternate, if there are two leaves they are opposite and if there are more than two they are whorled.
Alternate Opposite Leaves in whorls
*note some items in the exam may be taken from the supplements posted
Supplement - Roots
Roots are the principal water-absorbing organs of a plant. They are present on essentially all vascular plants. In fact, a root, by definition, must have vascular tissues, i.e., water conduits in xylem and sugar conduits in phloem, arranged in a particular way ("exarch"). Much thinner, threadlike rhizoids (means "root-like") are present on the nonvascular plants, such as mosses and liverworts, and on gametophytes of vascular plants without seeds, such as ferns, horsetails, and club mosses. Rhizoids also absorb water but totally lack vascular tissues.
There are three primary functions of roots: (1) to anchor the plant to a substrate, (2) to absorb water and dissolved minerals, and (3) to store food reserves. Typically we see roots in soil, but there are specialized types of aerial roots (air roots) that enable climbing plants and epiphytes to become attached to rocks, bark, and other nonsoil substrates. In addition, parasitic plants may form specialized haustorial roots that form an attachment disc to the host during the first stage of colonization. To absorb water and dissolved minerals, a young sector of a root commonly possesses numerous single-celled projections called root hairs, which greatly increase the absorbing surface of the root and achieve much greater contact with soil particles. Water uptake into the young root is rapid because there is little resistance through the outer cell walls, and in general these walls contain virtually no water-repellent wax (cutin). Both young and old roots can be important repositories for carbohydrates, usually in the form of starch grains located in root cortex, but in addition older roots may store massive quantities of starch and even become specialized below-ground storage organs. Storage of carbohydrates in roots and other below-ground plant organs is an important plant strategy for surviving stress and dormancy, just as certain mammals store extra fuel as fat for winter.
The radicle is the initial root of a plant, the one that is generally present on the embryo within the seed. This forms the primary root of a young plant. In certain lineages, the embryo is so tiny and immature, such as in microseeds of orchids (Family Orchidaceae), that a radicle is not present.
There are several possible fates of the primary root.
In gymnosperms and dicotyledons, the primary root commonly grows to become a thick central root, the taproot, which may or may not have thick lateral roots (branches). This structural organization is frequently termed a taproot system.
In monocotyledons, the radicle is very short-lived, and before it dies other adventitious roots have already originated from shoot or mesocotyl tissue to become the new root system, called a fibrous root system
Adventitious roots: adventitious roots arise out of stems. In some plants leaves can also be encouraged to form adventitious roots. Examples: adventitious roots of a palm; of a Canary Island date palm; specialized adventitious roots of an epiphytic orchid; of an aquatic plant that has unattached roots in moving water] Certain "root crops" that botanically are below-ground shoots, such as tubers, bulbs, rhizomes, and corms, form adventitious roots when planted in soil.
Vegetative reproduction (apomixis) of cacti and other succulent plants is also achieved largely by rooting either stems or leaves using methods to stimulate adventitious root formation.
Specialized Variations of Roots:
• Nodal roots: adventitious roots that form characteristically in rings from stem tissues around a node.
• Aerial roots: roots that are formed in and exposed to air, e.g., by epiphytes and hemiepiphytes; in some species, aerial roots grow downward from the tropical tree canopy toward the ground as extremely long, unbranched roots.
• Prop or stilt roots: adventitious roots that develop on a trunk or lower branch that begin as aerial roots (another example; reaching for the water) but eventually grow into a substrate of some type; these roots in some cases seem to provide mechanical support, having either good compression or tensile properties to help support trees at their bases.
• Buttress or tabular roots: vertically flattened roots that project out of the ground and lower trunk at the base of large trees. Models have suggested how these buttresses provide additional tensile forces to resist uprooting of large tropical trees.
• Contractile roots: roots that become shortened in length (shrivel or shrink in length) and thereby draw the plant or plant part downward into the soil profile; many examples can be found among bulbous plants.
• Pneumatophores: spongy, aerial roots of marsh or swamps, such as in mangal (mangroves), where roots are present in waterlogged soils and cannot obtain enough oxygen for maintaining healthy tissues. Here, pneumatophores are "breathing roots" that are emergent, and they have special air channels (lenticels) for gas exchange in the atmosphere (air enters at zones called "pneumathodes") and there is an internal pathway for getting O2 into the root and to supply submerged roots. The aerial loop of a mangrove root is sometimes called a "knee" or "peg root," but it is not clear that knees are necessarily breathing roots.
• Caudex or lignotuber: a taproot that has fused with the stem may become woody. Lignotubers often occur in seasonally dry or fire-prone habitats, and the plants appear to use this strategy to recover from dormancy or fire.
• Haustorial root: the root of particular parasitic plants that become cemented to the host axis via a sticky attachment disc before the root or sinker intrudes into the tissues of the host.
• Strangling roots: the special name for roots of strangling figs (Ficus), which are primary hemiepiphytes that begin life as tropical epiphytes in trees and send down adventitious roots that become rooted in the soil. The roots surround the host trunk, eventually strangling the bark and killing the host tree.
• Root tubers: swollen portions of a root that can have buds to produce new shoots; when broken off, these can grow into a new plant, so this is a form of cloning. In the older literature, these were sometimes referred to as fascicled roots.
*note some questions in the exam maybe found here
There are three primary functions of roots: (1) to anchor the plant to a substrate, (2) to absorb water and dissolved minerals, and (3) to store food reserves. Typically we see roots in soil, but there are specialized types of aerial roots (air roots) that enable climbing plants and epiphytes to become attached to rocks, bark, and other nonsoil substrates. In addition, parasitic plants may form specialized haustorial roots that form an attachment disc to the host during the first stage of colonization. To absorb water and dissolved minerals, a young sector of a root commonly possesses numerous single-celled projections called root hairs, which greatly increase the absorbing surface of the root and achieve much greater contact with soil particles. Water uptake into the young root is rapid because there is little resistance through the outer cell walls, and in general these walls contain virtually no water-repellent wax (cutin). Both young and old roots can be important repositories for carbohydrates, usually in the form of starch grains located in root cortex, but in addition older roots may store massive quantities of starch and even become specialized below-ground storage organs. Storage of carbohydrates in roots and other below-ground plant organs is an important plant strategy for surviving stress and dormancy, just as certain mammals store extra fuel as fat for winter.
The radicle is the initial root of a plant, the one that is generally present on the embryo within the seed. This forms the primary root of a young plant. In certain lineages, the embryo is so tiny and immature, such as in microseeds of orchids (Family Orchidaceae), that a radicle is not present.
There are several possible fates of the primary root.
In gymnosperms and dicotyledons, the primary root commonly grows to become a thick central root, the taproot, which may or may not have thick lateral roots (branches). This structural organization is frequently termed a taproot system.
In monocotyledons, the radicle is very short-lived, and before it dies other adventitious roots have already originated from shoot or mesocotyl tissue to become the new root system, called a fibrous root system
Adventitious roots: adventitious roots arise out of stems. In some plants leaves can also be encouraged to form adventitious roots. Examples: adventitious roots of a palm; of a Canary Island date palm; specialized adventitious roots of an epiphytic orchid; of an aquatic plant that has unattached roots in moving water] Certain "root crops" that botanically are below-ground shoots, such as tubers, bulbs, rhizomes, and corms, form adventitious roots when planted in soil.
Vegetative reproduction (apomixis) of cacti and other succulent plants is also achieved largely by rooting either stems or leaves using methods to stimulate adventitious root formation.
Specialized Variations of Roots:
• Nodal roots: adventitious roots that form characteristically in rings from stem tissues around a node.
• Aerial roots: roots that are formed in and exposed to air, e.g., by epiphytes and hemiepiphytes; in some species, aerial roots grow downward from the tropical tree canopy toward the ground as extremely long, unbranched roots.
• Prop or stilt roots: adventitious roots that develop on a trunk or lower branch that begin as aerial roots (another example; reaching for the water) but eventually grow into a substrate of some type; these roots in some cases seem to provide mechanical support, having either good compression or tensile properties to help support trees at their bases.
• Buttress or tabular roots: vertically flattened roots that project out of the ground and lower trunk at the base of large trees. Models have suggested how these buttresses provide additional tensile forces to resist uprooting of large tropical trees.
• Contractile roots: roots that become shortened in length (shrivel or shrink in length) and thereby draw the plant or plant part downward into the soil profile; many examples can be found among bulbous plants.
• Pneumatophores: spongy, aerial roots of marsh or swamps, such as in mangal (mangroves), where roots are present in waterlogged soils and cannot obtain enough oxygen for maintaining healthy tissues. Here, pneumatophores are "breathing roots" that are emergent, and they have special air channels (lenticels) for gas exchange in the atmosphere (air enters at zones called "pneumathodes") and there is an internal pathway for getting O2 into the root and to supply submerged roots. The aerial loop of a mangrove root is sometimes called a "knee" or "peg root," but it is not clear that knees are necessarily breathing roots.
• Caudex or lignotuber: a taproot that has fused with the stem may become woody. Lignotubers often occur in seasonally dry or fire-prone habitats, and the plants appear to use this strategy to recover from dormancy or fire.
• Haustorial root: the root of particular parasitic plants that become cemented to the host axis via a sticky attachment disc before the root or sinker intrudes into the tissues of the host.
• Strangling roots: the special name for roots of strangling figs (Ficus), which are primary hemiepiphytes that begin life as tropical epiphytes in trees and send down adventitious roots that become rooted in the soil. The roots surround the host trunk, eventually strangling the bark and killing the host tree.
• Root tubers: swollen portions of a root that can have buds to produce new shoots; when broken off, these can grow into a new plant, so this is a form of cloning. In the older literature, these were sometimes referred to as fascicled roots.
*note some questions in the exam maybe found here
Plant Parts - Function and Structure
Plants continue to grow as long as they live because they contain tissue called meristem that continually divides and generates new cells
Primary growth – elongation of the plant down into the soil and up into the air.
Secondary growth – increase in girth
Apical meristem found at the tips of the root and in the buds of short is the source of primary growth.
Lateral meristem – provides secondary growth.
- absorb nutrients from the soil,
- anchor the plant
- store food
Structure
Epidermis – covers the entire surface of the root and is modified for absorption
Root hairs – cytoplasmic projections that increase absorption
Cortex – consists of parenchymal cells that contain many plastids for the storage of starch and other substances
Stele – consists of vascular tissue surrounded by one or more layers of tissue called the pericycle, from which lateral roots arise.
Endodermis – surrounds the vascular cylinder or the stele. Composed of cells wrapped with the Casparian strip, a continuous band of suberin, a waxy material impervious to water and dissolved minerals. Selects what minerals enter the stele and the plant body.
Three zones of cells at different stages of primary growth
Zone of cell division / Apical meristem – meristem cells that are actively dividing
- responsible for producing new cells that grow down into the soil.
Zone of elongation – Cells elongate and are responsible for pushing the root cap downward deeper into the soil
Zone of differentiation – cells undergo specialization into three primary meristems that give rise to three tissue systems in the plant:
1. protoderm – becomes the epidermins
2. ground meristem – becomes the cortex (for storage)
3. procambium – becomes the primary xylem and phloem
Types of Roots
Taproot – single, large root that give rise to lateral branch roots
- common in dicots
- maybe modified for storage
Fibrous root system – holds the plant firmly in place
- common in monocots like grasses
Primary growth – elongation of the plant down into the soil and up into the air.
Secondary growth – increase in girth
Apical meristem found at the tips of the root and in the buds of short is the source of primary growth.
Lateral meristem – provides secondary growth.
Roots
Function- absorb nutrients from the soil,
- anchor the plant
- store food
Structure
Epidermis – covers the entire surface of the root and is modified for absorption
Root hairs – cytoplasmic projections that increase absorption
Cortex – consists of parenchymal cells that contain many plastids for the storage of starch and other substances
Stele – consists of vascular tissue surrounded by one or more layers of tissue called the pericycle, from which lateral roots arise.
Endodermis – surrounds the vascular cylinder or the stele. Composed of cells wrapped with the Casparian strip, a continuous band of suberin, a waxy material impervious to water and dissolved minerals. Selects what minerals enter the stele and the plant body.
Three zones of cells at different stages of primary growth
Zone of cell division / Apical meristem – meristem cells that are actively dividing
- responsible for producing new cells that grow down into the soil.
Zone of elongation – Cells elongate and are responsible for pushing the root cap downward deeper into the soil
Zone of differentiation – cells undergo specialization into three primary meristems that give rise to three tissue systems in the plant:
1. protoderm – becomes the epidermins
2. ground meristem – becomes the cortex (for storage)
3. procambium – becomes the primary xylem and phloem
Types of Roots
Taproot – single, large root that give rise to lateral branch roots
- common in dicots
- maybe modified for storage
Fibrous root system – holds the plant firmly in place
- common in monocots like grasses
Stem
Leaf
Wednesday, August 18, 2010
Multicellular organization - Plants (Tissues)
Three types
o dermal tissue
o vascular tissue
o ground tissue
Dermal tissue
- covers and protects plants.
- Includes the epidermis and modified cells like guard cells, root hairs, and cells that produce a waxy cuticle.
Vascular tissue
- consists of phloem and xylem
- these transport water and nutrients around the plant
xylem
- the water and mineral conducting tissue, consists of two types of elongated cells: tracheids and vessel elements
- both tracheids and vessel elements are dead at functional maturity.
- Seedless vascular plants and most gymnosperms have only tracheids
- Angiosperms have both tracheids and vessel members
- Xylem is what makes up wood.
*Tracheids - long thin cells that overlap and are tapered at the ends.
* Vessel elements - generally wider, shorter, thinner walled and less tapered than tracheids.
- aligned end to end and differ from tracheids in that the ends are perforated to allow free flow through the vessel tubes.
Phloem
- carries sugars from the photosynthetic leaves to the rest of the plant by active transport.
- Consists of chains of sieve tube members or elements whose end walls contain sieve plates that facilitate the flow of fluid from one cell to the next.
- Alive at functional maturity, although they lack nuclei, ribosome and vacuoles. Connected to each sieve tube member is at least one companion cell that does contain a full complement of cell organelles and nurtures the sieve tube elements.
Ground tissue
- the most common type of tissue
- functions mainly as support, storage and photosynthesis
- consists of three cell types: parenchyma, sclerenchyma and collenchyma
Parenchyma cells
- look like classic plant cells
- have primary cells walls that are thin and flexible
- lack secondary cell walls
- protoplasm contains one large vacuole and the cell carries out most metabolic functions
- parenchymal cells in the leaf (mesophyll cells) contain chloroplasts and carry out photoynthesis
- parenchymal cells in roots contain plastids and store starch
- if turgid with water, they give support and shape to the plant.
- Most parenchymal cells retain the ability to divide and differentiate into other cell types after a plant has been injured in some way.
- Once parenchymal cell may regenerate or clone an entire plant
Collenchyma cells
- have unevenly thickened primary cell walls but lack secondary cell walls
- mature collenchymal cells are alive and their function is to support the growing stem
Scelerenchyma cells
- have thick primary and secondary cell walls fortified with lignin
- function is to support the plant
- two forms: sclereids and fibers
* fibers – are long thin and fibrous like and usually occur in bundles
- commercially used to make rope and flax fibers
* sclereids – short and irregular in shape.
- make up tough seed coats and pits
- give pears its gritty texture
o dermal tissue
o vascular tissue
o ground tissue
Dermal tissue
- covers and protects plants.
- Includes the epidermis and modified cells like guard cells, root hairs, and cells that produce a waxy cuticle.
Below are the dermal layers of a leaf
Vascular tissue
- consists of phloem and xylem
- these transport water and nutrients around the plant
xylem
- the water and mineral conducting tissue, consists of two types of elongated cells: tracheids and vessel elements
- both tracheids and vessel elements are dead at functional maturity.
- Seedless vascular plants and most gymnosperms have only tracheids
- Angiosperms have both tracheids and vessel members
- Xylem is what makes up wood.
Wood
*Tracheids - long thin cells that overlap and are tapered at the ends.
* Vessel elements - generally wider, shorter, thinner walled and less tapered than tracheids.
- aligned end to end and differ from tracheids in that the ends are perforated to allow free flow through the vessel tubes.
Phloem
- carries sugars from the photosynthetic leaves to the rest of the plant by active transport.
- Consists of chains of sieve tube members or elements whose end walls contain sieve plates that facilitate the flow of fluid from one cell to the next.
- Alive at functional maturity, although they lack nuclei, ribosome and vacuoles. Connected to each sieve tube member is at least one companion cell that does contain a full complement of cell organelles and nurtures the sieve tube elements.
Below is an image of a sieve tube member
Ground tissue
- the most common type of tissue
- functions mainly as support, storage and photosynthesis
- consists of three cell types: parenchyma, sclerenchyma and collenchyma
Below are ground tissue cells
Parenchyma cells
- look like classic plant cells
- have primary cells walls that are thin and flexible
- lack secondary cell walls
- protoplasm contains one large vacuole and the cell carries out most metabolic functions
- parenchymal cells in the leaf (mesophyll cells) contain chloroplasts and carry out photoynthesis
- parenchymal cells in roots contain plastids and store starch
- if turgid with water, they give support and shape to the plant.
- Most parenchymal cells retain the ability to divide and differentiate into other cell types after a plant has been injured in some way.
- Once parenchymal cell may regenerate or clone an entire plant
Collenchyma cells
- have unevenly thickened primary cell walls but lack secondary cell walls
- mature collenchymal cells are alive and their function is to support the growing stem
Scelerenchyma cells
- have thick primary and secondary cell walls fortified with lignin
- function is to support the plant
- two forms: sclereids and fibers
* fibers – are long thin and fibrous like and usually occur in bundles
- commercially used to make rope and flax fibers
* sclereids – short and irregular in shape.
- make up tough seed coats and pits
- give pears its gritty texture
Multicellular organization - Plants (Introduction)
Plants
- multicelled, eukaryotic, photosynthetic autotrophs- life cycle of plants is characterized by alternation of generation
o gametophyte generation: cells of the plant body are haploid (n)
o sporophyte generation: cells of the plant body are diploid(2n)
Alternation of Generation
- 300,000 species
- Stabilize the soil they live in and provide a home for billions of insects and larger animals
- Release O2 and absorb CO2
- organized into two groups
o bryophytes
o tracheophytes
Bryophytes
- non vascular plants ex. Mosses, liverworts and hornworts
- primitive plants that lack transport vessel (xylem and phloem)
- absorb H2O by diffusion from the air
- flagellated sperm must swim through water to fertilize an egg.
- Lack any lignin fortified tissue
- Restricted to moist habitat and are tiny
- Grow on rocks, soil and trees
- Ex. Sphagnum or peat moss
Below are images of different bryophytes
Below is an image of a moss sperm
Tracheophytes
- have xylem and phloem for transport of nutrients
- lignified transport vessels to support the plant
- roots to absorb water while also anchoring and supporting the plant
- leaves that increase the photosynthetic surface
- life cycle with a dominant sporophyte generation
- divided into two
o with seeds ex. gymnosperms and angiosperms
o without seeds ex. Ferns
Ferns
- seedless plants
- reproduce via spores instead of seeds
- spores are homosporous that produce only one type of spore which then develops into a bisexual gametophyte.
- Still restricted to moist habitats
- Sperm is flagellated and must swim from male gametophyte (antheridium) to the female gametophyte (archegonium) to fertilize the egg.
Seed plants
- heterosporous that produces two kinds of spores i.e megaspore and miscrospore
o megaspore – male gametophytes
o microspore – female gametophyte
- sperm are not flagellated so do note require moist environment
homospory and heterospory
- first seed plants to appear on earth
- seeds are “naked” because they are not enclosed inside a fruit
- seeds are exposed on modified leaves that form cones which are better adapted for a dry environment
- other modifications include needle shaped leaves, thick, protective cuticle and relatively small surface area.
- depend on wind pollination
- Ex. Pines, firs, redwood, juniper and sequoia
Below is a picture of a naked pine seed
Below is an image of a Sequoia tree
Angiosperm
- seed plants whose reproductive structures are flowers and fruits
- most diverse plant specie including 90% of all plants
- color and scent of a flower attracts animals that will carry pollen from one plant to another across distances
- after pollination and fertilization the ovary becomes the fruit and the ovule becomes the seed.
- The fruits protects the dormant seeds and aids their dispersal
- There are two groups of angiosperms
o Monocots
o Dicots
- seed plants whose reproductive structures are flowers and fruits
- most diverse plant specie including 90% of all plants
- color and scent of a flower attracts animals that will carry pollen from one plant to another across distances
- after pollination and fertilization the ovary becomes the fruit and the ovule becomes the seed.
- The fruits protects the dormant seeds and aids their dispersal
- There are two groups of angiosperms
o Monocots
o Dicots
Below are flowering plants
Saturday, August 14, 2010
Plants lecture handouts
Sorry guys. I just had a death in the family. we will just have a class on monday or wednesday depending on whether its a holiday or not.
Thursday, August 5, 2010
Mitosis and Meiosis videos
Here is a videos of Mitosis and Meiosis taken from Youtube. These would help in better understanding these processes
Mitosis
Meiosis
Wednesday, August 4, 2010
Module 5 - Cellular Basis of Life (Part 2)
Two types of cells
1. Prokaryotic Cell
- Prokaryotic means “before the nucleus”
- Comprised of Domain Bacteria and Archaea
2. Eukaryotic Cell
- eu means “true” and karyon means kernel or the nucleus.
- all eukaryotic cells start life with a nucleus and other membrane-enclosed organelles
ORGANELLE – a structure that carries out a specialized function inside a cell
1. Prokaryotic Cell
- Prokaryotic means “before the nucleus”
- Comprised of Domain Bacteria and Archaea
2. Eukaryotic Cell
- eu means “true” and karyon means kernel or the nucleus.
- all eukaryotic cells start life with a nucleus and other membrane-enclosed organelles
ORGANELLE – a structure that carries out a specialized function inside a cell
Module 5 - Cellular Basis of Life
The cell is the lowest level of structure capable of performing all activities of life.
Discovery of the cell
Robert Hooke (1665)
- English scientist, first described and named cells.
- Observed in a slice a cork and saw that the compartments / tiny boxes or cells were unique to cork.
Anton van Leeuwenhoek (1674)
- Dutchman who first saw live cells using grains of sand polished into magnifying glasses.
- Saw a microbial world in droplets of pond water and also observed blood cells and sperm cells of animals.
Matthias Schleiden and Theodor Schwann (1839)
- German biologists, reached a generalization based on many concurring observations reaching a generalization that all living things consists of cells.
Rudolph Virchow (1858)
- German doctor, concluded that all cells come from pre-existing cells based on his study on how cells reproduce.
*****
Cell Theory
1. All living things are composed of cells.
2. A cell is the smallest unit with the properties of life.
3. Each new cell arises from division of another, preexisting cell.
4. Each cell passes hereditary material to its offspring.
Discovery of the cell
Robert Hooke (1665)
- English scientist, first described and named cells.
- Observed in a slice a cork and saw that the compartments / tiny boxes or cells were unique to cork.
Anton van Leeuwenhoek (1674)
- Dutchman who first saw live cells using grains of sand polished into magnifying glasses.
- Saw a microbial world in droplets of pond water and also observed blood cells and sperm cells of animals.
Matthias Schleiden and Theodor Schwann (1839)
- German biologists, reached a generalization based on many concurring observations reaching a generalization that all living things consists of cells.
Rudolph Virchow (1858)
- German doctor, concluded that all cells come from pre-existing cells based on his study on how cells reproduce.
*****
Cell Theory
1. All living things are composed of cells.
2. A cell is the smallest unit with the properties of life.
3. Each new cell arises from division of another, preexisting cell.
4. Each cell passes hereditary material to its offspring.
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