Bio 2150 Exam 2

Do arechaea and bacteria have organelles?

Do arechaea and bacteria have organelles?

No

Bacterial cell

chromosomal DNA in a loop (plasmid)

antibiotic resistance is found in plasmid

cell wall- peptidoglycan and plasmid membrane

myxobacterium

cells form fruiting bodies when food is scarce

thick cells walls are able to survive tough conditions

Horizontal gene transfer

bacteria reproduce asexually

bacteria obtain new genes from other bacteria

less diverse, genes from one source not two

Conjugation

DNA in a plasmid from a donor cell is transferred through a pilus into a recipient cell

Transformation

DNA released into the environment by dead cells is taken up by a recipient cell

Transduction

DNA is transferred from a donor cell to a recipient cell by a virus

What limits the size of cells?

Surface area to volume ratio

Characteristics of Archaea

membranes have lipid composition

no peptidoglycan in cell walls

many inhabit extreme environments

Photosynthesis

CO2 is reduced to carbohydrates

oxygenic in eukaryotes

Respiration

carbohydrates are oxidized to CO2

O2 serves as an electron acceptor

Phototrophs

energy from the sun

Chemotrophs

energy from chemical compounds

Autotrophs

carbon from inorganic molecules (CO2)

Heterotrophs

carbon from organic molecules (glucose)

O2 and H2S in microbial mats

not in same environment

Photoheterotrophs

energy from sunlight to make ATP

do not reduce CO2 to make own organic molecules

environments rich in organic material but not in oxygen

exclusively prokaryotes

Chemoautotrophs

gain carbon by reducing CO2 to form carbs

oxidation of inorganic molecules to drive ATP synthesis

exclusively prokaryotes

What organisms can function as chemoautotrophs?

bacteria and archaeons

Nitrogen fixing

converting N2 into a useful form like NH3

Nitrification

NH3 is released by dead cells, is taken up by primary producers, also used to oxidize nitrate by chemoautotropic bacteria

Denitrification

use nitrate as an electron acceptor in respiration, returns N2 gas to the air

Proteobacteria

most diverse bacterial group

bacteria that populate the expanded carbon cycle and the other biogeochemical cycles

intimate ecological relationships with eukaryotic organisms

Gram staining

gram positive bacteria have a thick wall of peptidoglycan and train die

Gram-positive bacteria cause disease

strep

Gram-positive bacteria cure disease

antibiotics

Archaeons often live where

energy and resources are too low to support bacteria and eukaryotes

Why are Eukaryotes successful?

only oxygenic photosynthesis

minimal anaerobic respiration

diverse shapes and sizes

dynamic cytoskeleton and membrane

can form multicellular structures

Eukaryotic cells

larger than prokaryotic cells

membrane bound organelles

multiple linear chromosomes

What is found in both prokaryotic and eukaryotic cells?

Ribosomes

What is true about meiosis and mitosis?

Meiosis produces haploid cells from diploid cells

Endosymbiosis

living together with benefit

living inside one another

Where did chloroplast originate?

engulfed cyanobacteria

Where did mitochondria originate?

engulfed proteobacteria

Evidence for chloroplast and mitochondria origination (endosymbiosis)

two membranes

contain DNA

internal membrane structures similar to free-living bacteria

Protists

have a nucleus

lack features specific to plants, animals, or fungi

Algae

photosynthetic protists

Protozoa

heterotropic protists

don't undergo photosynthesis

glucose main from of energy

Opisthokonta

75% of species

chanoflagellates, most closely related to animals

animal genes found in them

Amoebozoans

move using pseudopodia

soil predators

slime molds

multiple nuclei in one cell

Archaeplastids

plants, land plants

most of biomass on Earth

Red algae

most marine organisms

seaweeds

toothpaste, ice cream, agar

Green algae

what land plants evolved from

very diverse

Stramenopiles

ocean silica shells (diatoms)

precipitate silica

ends up on bottom of ocean

25% of photosynthesis comes from them

What group has the most ancesteral chloroplasts?

glaucocystophytes

How did eukaryotes acquire photosynthesis?

multiple times by repeated episodes of endosymbiosis

Which group of protists have calcium carbonate skeletons

red algae

Simply multicellularity

cells stick together

every cell in direct contact with external environment

little cell specialization or communication

most still have a full range of function

Reasons for multicellularity

provide protection

maintain position in environment

easier feeding

In simple multicellularity,

most cells retain a full range of function

Complex multicellularity,

advanced mechanisms for cell adhesion

3-D organization

specialized structure for cell communication

differentiated cells and tissues

What sets size limits on single cells?

movement of materials within the cells

Diffusion

the process of random movement toward equilibrium

net movement from regions of high solute concentration to lower solute concentration

Bulk transport

molecules move through organisms at rates beyond those possible by diffusion across a concentration gradient

Cadherins

adjacent cells adhere to one another by means of transmembrane proteins

Integrin

bind to ECM

secrete an extracellular matrix

Pectins

plant cell adhesive molecules

Gap junctions

protein channel that directly connects cells

move molecules between cells

Zygote undergoes mitosis to form a...

blastula (hollow ball)

blastula cells migrate to form a gastrula, cell differentiation occurs

How can the cells within your body become different cells?

they are in difference local environments, genes are regulated

Regulatory genes

code for proteins that regulate the activity of other genes

Bryophytes

no roots

don't control hydration

Vascular plants

roots

control hydration

95% of land plants

Whats an example of a vascular plant?

a rose bush

Shoot of a vascular plant includes

reproductive organs, leaf, and stem

Stoma

where CO2 enters

Transpiration in a plant

100 H2O molecules lost

1 CO2 molecule entering

higher concentration difference in terms of water, diffuses faster

Closed stomata

release of solutes causes water to flow out of the guard cells closing the stoma

(default)

Open stomata

uptake of solutes by guard cells causes water to be drawn in by osmosis. as the guard cells swell, they bow apart, open the stoma

let in carbon, let out oxygen (but water is lost)

CAM photosynthesis

-stomata open at night, CO2 enters and stores in a vacuole (C4)

-stomata close during the day, CO2 is converted back to be used in calvin cycle

avoid day water loss

Guard cells

control volume by altering concentration of K+ and Cl-

more solutes means more water in cells, causing them to swell

Photorespiration

O2 as a substrate results in a net loss of energy and release of CO2- happens when there is a lot of oxygen in the environment

C4 plants/photosynthesis

suppress photorespiration by increasing CO2 in the immediate vicinity of rubisco

CO2 capture and calvin cycle occur in differnt cells, allows for suppressed photorespiration

Xylem

transports water and nutrients from roots to leaves

Phloem

transports carbohydrates from leave to rest of plant

How do plants get water?

transpiring plants lift water up high and fast

no energy required

H-bonds in water allow it to be pulled through xylem

Risks associated with xylem transport

collapse, cavitation, and bubble formation

Water transport in xylem depends on

cohesion between H2O molecules

Source

regions that produce or store carbohydrates (leaves)

Sink

region that needs carbohydrates to fuel growth and respiration (roots)

Tugor pressure

difference in tugor pressure drives movement of phloem sap from source to sink

What would be considered a carbohydrate sink in vascular plants?

stem and roots

Distribution of carbohydrates

50% of carbs produced by a plant are converted back to CO2 within 24 hrs

Rhizosphere

soil layer that surrounds actively growing roots

Casparian strip

hydrophobic, blocks flow of water and nutrients

in a root

Mycorrizae increase nutrient uptake for plants. What do they get in return?

Carbohydrates produced by the plant

Sporophyte

2n, produces spores by meiosos

spores develop into the haploid (1n) gametophyte

spore walls contain sporopollenin (resistant to UV radiation and desication)

larger and independent of the gametophyte

Gametophyte

1n, produces gametes by mitosis

What are haploid?

gametophyte, spores

Advantages of gamete and offspring dispersal

outcrossing, genetic diversity

nutrient supply, less competition for nutrients

pathogen/parasite avoidance, dispersal results in fewer interactions

Germination

growth of plant from a seed

Cone

produces spores (reproductive structure)

Ovule

contains egg

Meiosis creates pollen...

pollen (sperm) interacts with egg within the ovule

ovule turns into seeds after fertilization

Seed production

fertilization is independent of water

gametophyte is reduced to a few cells dependent on the sporophyte

seeds are able to disperse away from parent plant

Seed diversity

seeds store resources

low metabolic activity

some seeds exhibit dormancy

variable sizes

Flower diversity

flower evolution allowed for the use of animals for pollination

increased efficiency of pollination

Petals and sepals

attract pollinator and protect the flower`

Carpals and Stamens

carpals- produce ovules

stamen- produce pollen

Self-compatible

pollen and eggs form the same plant can unite to form offspring