Bio lab exam III

Gymnosperms

Gymnosperms

"Naked" seed, not enclosed in a fruit. Include conifers, which produce cones during sexual reproduction.

Pollen cone

• Male cone, usually smaller in size than a female cone

• each scale of the cone contains one microsporangium, which undergoes meiosis to create microspores, which undergo mitosis to produce the microgametophyte

pollen grain

• male gametophyte

• one of these contains 2 living cells (one is sperm nucleus) and 2 dead cells that form "wings" to help it travel through the air

Life cycle of a seeded plant

seed cone

• female cone, usually larger in size than a male cone

• each ovule contains one scale, a megasporangium which undergoes meiosis to megaspores, which undergo mitosis to produce the megagametophyte

Megasporangium

• black bracket

• undergoes meiosis

• one in each scale of a seed cone

Megagametophyte

• red oval

• undergoes mitosis to produce eggs

Archegonium

white layer of cells surrounding eggs

Eggs

• 2 black arrows

• undergo fertilization by combining with sperm to form embryo in seed, which grows into sporophyte

1st spring in seeded plant cycle

• scales on ovulate cone are open to allow pollen in

• scales close and allow pollen inside

• over the next year, the megagametophyte develops and produces eggs while tapped pollen grains wait

2nd spring in seeded plant cycle

• sperm fuses with egg and grows into embryo in the seed

• seed coat and stored food develop from megasporangium and megagametophyte tissue

Benefits of seed dormancy

• seeds can dry out completely and still be alive

• seeds can remain dormant for a VERY long time and still germinate when exposed to the proper conditions

Contents of a seed, function, and ploidy

• seed coat protects embryo (2n)

• food supply provides energy to embryo when seed germinates (n)

• embryo is baby plant (2n)

Angiosperm

Seed is covered by a fruit, includes flowering plants

Parts of a flower

• stamen (male) (red)

• anther (orange)

• filament (yellow)

• stigma (light green)

• style (mid green)

• ovary (female) (dark green)

• carpel (blue)

• petals (purple)

• receptacle (pink)

• ovule (grey)

• sepal (black)

Pollination of flowering plants

Stigma traps pollen from air and it travels through the style to the ovule. Plants with petals rely on pollinators for this, while plants without petals rely on the wind.

Flower is defined as

the presence of stamens and/or carpels, not petals

Double fertilization (flowering plants only)

• megagametophyte is only 7 cells

• large cell in center is made up of 2 polar nuclei

• when this cell is fertilized it is triploid, with 2 sets of eggs and 1 set of sperm chromosomes

• this cell grows to form endosperm which provides food in the seed

Main function of fruits

To aid in dispersal. Animals eat fruits and poop out seeds, thereby dispersing plant.

cross section of flowering plant

What is arrow pointing to?

Microspores, which grow into microgametophyte (pollen)

Where can growth only occur in plants? How do cells in those places divide?

Meristems; mitosis

Apical meristems

• growth in length

• know as primary (1 degree) growth

• happens at root tips and shoot tips

Lateral meristems

• also called cambium

• growth in width

• known as secondary (2 degree) growth

• trees have a lot, grass has none

Function of root cap

To protect apical meristem

Function of roots hairs on radish seedling

increase surface area for absorption of water/nutrients from soil

Coleus stem tip

1. leaf primordia

2. young leaf

3. shoot apical meristem

4. bud primordia

Parenchyma

• living

• relatively thin cell walls

• function in storage

• may or may not have chloroplasts

• pretty big, found in pretty much everything

Collenchyma

• found in celery

• living

• thicker cell walls provide flexible support

• smaller cells

Sclerenchyma

• found in pear skins and gives them their gritty texture

• can be in sclereid (what we saw in lab) and fiber forms

• cells dead at maturity

• very thick cell walls provide rigid support

Xylem

• long, vessel-like structures used for water transport

• dead at maturity

Phloem

• used for sugar transport

• living cells with nucleated companion cells

Leaf epidermis

• stoma (yellow arrow)

• guard cells (black arrow)

• parenchyma (green arrow)

Function of guard cells

Control when stoma open and close, which prevents water loss

Function of stomata

allows for intake of CO2 and excretion of O2

Celery

• vascular bundles (black arrow)

• parenchyma (yellow arrow)

• collenchyma (green arrow)

Potato

• leucoplasts (blue arrow)

• cell wall (black arrow)

Where leucoplasts are found and their function

Potatoes; starch storage

Pear

• slcereid form of sclerenchyma (blue arrow)

• parenchyma (black arrow)

Key differences between monocots and dicots

Monocots:

• one cotyledon

• parallel veins

• scattered vascular tissue

Dicots:

• two cotyledons

• netlike veins

• vascular tissue arranged in ring

Ranunculus (dicot root) zoomed in

• xylem (black arrow)

• phloem (green arrow)

Ranunculus (dicot root) zoomed out

1. epidermis

2. cortex

3. endodermis

4. vascular cylinder

parenchyma (black arrow)

Midrib Vein

1. collenchyma

2. xylem

3. phloem

Monocot stem vascular bundles

• xylem (purple and brown)

• phloem (yellow)

• sclerenchyma (red)

• parenchyma (green)

Dicot stem

• sclerenchyma (green)

• phloem (white)

• xylem (black)

• pith (purple)

• cortex (blue)

• orange (vascular bundle)

• epidermis (yellow)

Dicot vascular bundle

• sclerenchyma (green)

• phloem (white)

• vascular cambium (pink)

• xylem (black)

• parenchyma (blue)

Secondary growth is trees

• xylem accumulates each year and makes up most of "wood" of tree

• new phloem is produced and becomes part of bark, and older phloem collapses

Hyphae

Thin filaments that make up fungi

Mycelium

All of the hyphae that make up a single fungus individual

Septate hyphae

Walled hyphae

Nonseptate hyphae

Unwalled, coenocytic hyphae

Chitin

Structural polysaccharide that makes up fungal cell walls.

How do fungi digest large food particles?

Cell walls prevent fungi from ingesting large food particles, so fungi must secrete digestive enzymes into its environment that break down the food into smaller particles that the fungi can then absorb.

Saprotroph

most free living fungi are decomposers, AKA

Symbiosis

relationships in which organisms live together (sometimes one inside the other) and are dependent on each other

Mutualism

a relationship between 2 organisms in which both benefit

commensalism

a relationship in which one partner requires and benefits from the relationship but the other is neutral

Parasitism

one partner requires and benefits from the relationship and the other is harmed

ploidy of fungal hyphae

haploid; spores are produced by mitosis

Heterokaryotic

cytoplasm fuses but nuclei do not

Reproductive cycle of fungi

Zygomycota

many molds and mildews; found on strawberries

young zygosporangium of zygomycota

arrows pointing to gametangia

mature zygosporangium of zygomycota

notice diploid nuclei, arrows pointing to gametangia

Ascomycota

produce asexual spores called conidia, which bud off of the tips of hyphae called conidiophores

Penicillium

1. conidia

2. conidiophore

Plasmogamy

dikaryotic hyphae result from a plasmogamy between 2 different mating strains. Eventually, these dikaryotic hyphae grow into a fruiting body, in which a karyogamy occurs.

ascocarps

Contain asci (sacs) which contain ascospores

Basidiomycota

plasmogamy results in dikaryotic hyphae (n+n) that develop into basidiocarp in which karyogamy (2n nuclei) and meiosis will eventually occur

mushroom anatomy

• cap (blue)

• gills, which contain basidia on their surface (pink)

• stalk/stipe (yellow)

basidia

Mycorrhizae

mutualistic relationship between fungi and plant roots-- plants provide food for fungus and fungus provides increased absorption of water and minerals from soil as well as growth factors and antibiotics. Mycorrhizal networks connect plants, allowing them to communicate

lichen

mutualistic relationship between fungi and algae. alga provides food and sometimes nitrogen, and fungus provides support, protection, and acquisition of minerals

lichen anatomy

• fungal hyphae (yellow arrow)

• algal layer (orange arrow)

chi-square (X^2)

hypothesis test that compares collected data to predictions made based on hypothesis. it is used to determine if the deviation between your data and your predictions can be explained by random variation alone

chi-square formula

degrees of freedom formula

of cases - 1

for example, if you have 2 phenotypes, the degree of freedom = 1