BIO 1R Exam 2 Flashcard Hell mod 3

What four basic components are shared by all cells?

Plasma Membrane (regultes what leaeves and enters cell), Cytoplasm (contains cystol + cellular components + where many meetablolic rxns occur), DNA, Ribosomes (translate mRNA into proteins)

Which Cell was the first to evolve

Prokaryotic

What are the key differences between eukaryotic cells and prokaryotic cells (4)

• Much bigger in size

• Genetic material is bounded by a nucleus - seperation of the genome from the rest of the cell allows for more complexity

• Extensive internal array of membrane-bound organelles (compartments with specialized functions)

• Dynamic cytoskeleton allows cells to change shape, move, and engluf material while maintaining proper function

Describe the functions of the Nucleus, Rough and Smooth ER, Golgi Apparatus, Vesicles, Lysosomes, and Vacuoles

Nucleus —> Separates genetic material

Rough ER —> Protein synthesis + folding

Smooth ER —> Hormone synthesis + calcium storage + release

Golgi Apparatus —> Modifies + packages proteins and lipids

Vesicles —> Transport + stores materials inside cells

Lysosomes —> Digest + recycle cellular components

Vacuoles —> Store substances and help maintain turgor pressure (in plants)

What are the three domains of life and how are they related?

Bacteria —> Prokaryptes that include cyanobacteria

Archae —> Prokaryotes with distinct membrane chemistry — inhabit extreme environments

Eukarya —> organisms with eularyotic cells (animals, plants, fungi)

• Share ancestory to last universal common ancestor (LUCA)

What are the advantages of cellular compartmentalization? (5)

• Cell specialization

• Efficiency (because enzymes and substrates can be concentrated in the same location)

• Regulation (different environments in each compartment, IE lysosomes is very acidic)

• Protection

• Simultaneous rxns

How do materials move among organelles and the plasma membrane?

• Using transport vesicles

• Rough ER —> Golgi —> Membrane (exocytosis)

What evidence connects eukaryotes evolutionarily to Asgardarchaea?

Genetic similarity: Asgardachaea also has genes involved in cytoskeleton organization, membrane remodeling, and intracellular regulation

What is meant by the mixed evolutionary Ancestry of eukaryotic cells?

• Eukaryotes contain evolutionary contributions from different ancestral lingeages

Archael —> share genetic processing

Bacterial —> mitochondria originated from bacteria + bacterial genes transferred into the ancestral eukaryotic nuclear genome

Bacterial (plants) —> chloroplast came from cyanobacteria

Define endosymbiosis and explain the origins of mitochondria and chloroplasts (who discovered it and how)

Endosymbiosis = when one cell lives inside another and eventually becomes an integral part of it

Mitochondria and chloroplast both came from bacteria that the eukaryotes engulfed.

Lynn Margulis uses electron microscope to show similarities between cyanobacteria and chloroplast

What evidence supports the endosymbiotic origin of mitochondria and chloroplasts (4)?

• their own DNA

• bacteral-like ribosomes

• a double membrane

• division resembling binary fission

Primary versus secondary endosymbiosis (compare their results)

Primary: a eukaryotic cell engulfed a cyanobacterium. Results in a eukaryote with a chlorplast

Secondary: Another eukaryotic cell engulfed a photosynthetic eukaryote that already contained a chloroplast. Results in a new photosynthetic lineage

How does endosymbiosis explain the distribution of photosynthesis among eukaryotes?

• Photosynthesis in distantly related eukaryotic groups because of multiple, repeated endosymbiosis

IE primary endosymbiosis establishes photosynthesis in ancestral eukaryotic lineages, but secondary endosymbiosis transferred the bacteria into different eukaryotic groups which were sometimes lost

Why do organisms need both carbon and energy?

Carbon —> supplies framework of organic molecules

Energy —> powers the work needed to build and maintain an organism (movement, active transport, building molecules, growing..)

Distinguish autotrophs from heterotrophs and phototrophs from chemotrophs.

Autotrophs —> use inorganic carbon to build organic molecules (IE CO2)

Heterotrophs —> obtain carbon from existing organic molecules

Chemotrophs —> use chemical compounds to obtain energy

Why are carbon and energy sources independent classifications?

Carbon source does not equal energy source

How do the laws of thermodynamics apply to living systems? Why is energy released as heat?

Energy can only be transferred or transformed (light energy is transformed into chemical energy in organic compounds)

Energy cannot be fully transformed from one form to another — some has to be lost to the environment as heat through molecular motion

What does ATP stand for and what is it made out of

Adenosine triphosphate (Adenine, Ribose, Three phosphate groups)

What is ATP hydrolysis?

What ATP is hydrolyzed, H2O is added to remove a terminal phosphate group, creating ADP, inorganic phosphate, and free energy

Hydroloysis releases the energy in ATP

Anabolic versus Catabolic pathways

Anabolic —> makes complex molecules, REQUIRING energy

Catabolic —> breaks down molecules, RELEASING energy

State the overall purpose and interpret the overall equation for photosynthesis.

Photosynthesis: converts light energy into chemical energy using CO2 (the making of sugar)

Redox reaction

Identify the stroma, thylakoids, thylakoid lumen, and grana.

What are the two steps of photosynthesis?

Light Dependent > Light Independent

How is light energy absorbed?

Chlorophyll absorbs red and blue light

Carotenoids absorbs other wavelengths that protect photosynthetic cells

They work together in a photosystem

What are the steps to the light dependent reactions of photosynthesis (6)

1. Light excites electrons in Photosystems I and II

2. Splitting water supplies electrons and releases O2

3. Electron transport and the splitting of water builds up a proton gradient

4. ATP synthase uses proton gradient to make ATP

5. Electrons reduce NADP+ to NADPH (now carrying a proton)

6. ATP and NADP —> Calvin Cycle

What are the light independent reactions called and what are its steps (3)

The Calvin Cycle

1. CO2 enters the cycle by being combined with RuBP and RuBisCO

2. ATP and NADPH are used to convert fixed carbon into G3P (G3P goes on to supply carbon for sugars and other molecules)

3. 5 out of the 6 G3Ps regenerate RuBP

Where does the oxygen released by photosynthesis orginate?

Water, not CO2

Water gets split during light dependent reactions at Photosystem II

What is cellular respiration?

Converting food energy into ATP energy using redox reactions — glucose is oxidized into a series of small steps

How does the proton gradient drive ATP synthesis?

Chemiosmosis:

• Concentration of H+ is increased inside thylakoid lumen using electron transport

• proton electrochemical gradient develops across the thylakoid membrane

• H+ moves from lumen into stroma via ATP synthase

• Proton flow causes ATP synthase to spin, catalyzing ATP production

Explain the roles of RuBisCO and RuBP in carbon fixation.

RuBisCO - enzyme that catalyzes CO2 into RuBP

RuBP - a five carbon molecule that accepts CO2

Identify the four main stages, their locations, and major products of cellular respiration (note where CO2 is released)

Glycolysis — Cystol — Produces 2 net Pyruvate, 2 net ATP, and 2 NADH

Pyruvate Oxidation — mitochondrial matrix — 2 acetyl-CoA, 2 CO2, 2 NADH

Citric Acid Cycle (Krebs Cycle) - mitochondrial matrix - 4 CO2, 2 ATP/GTP, 6NADH, 2 FADH2

Oxidative phosphorylation - inner mitochondrial membrane - up to 28 ATP and 1 water

How does the electron transport chain support ATP production?

Located on inner mitochondrial membnrane — NADH and FADH2 donate electrons from the Krebs Cycle. Complexes in the membrane pump protons from the matrix into intermembarne space, and forms an electrochemical gradient. H+ flows back through ATP synthase and ATP is made.

What is oxygen's role in cellular respiration and which stage yields most ATP?

Oxygen = final electron acceptor — accepts electrons, and combines with prtons to form water. Oxydative phosphorylation produces the most of the ATP.

Identify the major membrane components (5) and explain phospholipid amphipathicity.

Integral proteins — embedded in the membrane

Peripheral proteins — associated with the membrane surface

Cholesterol — helps regulate membrane fluidity

Glycoproteins — proteins with carb chains for reognixtion and communication

Glycolipids — lipids with carb groups, also involved in recognition and stability

Heads are hydrophillic — tails are hydrophobic

Explain the fluid mosaic model and why fluidity matters.

Fluid mosaic = membranes are dynamic ; proteins and lipids can move within the membrane. This is important for trasport protein function, membrane fusion, vesicle formation, cell growth, cell signaling, and redistributing membrane proteins.

How does cholesterol affect fluidity at high and low temperatures?

Cholesterol is a fluidity buffer in animal cell membranes

High temp —> phospholipid mvmt is restrained, reducing fluidity

Low temp —> phospholipids do not pack too tighlty, maintaining fluidity

Distinguish passive from active transport and simple from facilitated diffusion.

Passive transport - no ATP needed

Active transport — energy is needed to move substances against chemical gradient

Simple diffusion — substances pass directly through lipid bilayer (O2 and CO2)

Facillitated diffusion — substances pass through ion channel or carrier proteins

How do channel proteins, carrier proteins, and aquaporins work?

Channel proteins — form hydrophillic pathways through membrains for specifici ions/molecules to pass

Carrier proteins — bind to a specific substance, undergoes a function change, and releases substance on the other side. works for active and passive transport

Aquaporins — allow rapid mvment of water, but does not pump water against its water-potential gradient

Distinguish primary and secondary active transport.

Primary active transport = directly uses an energy source to move against a gradient

Secondary = uses the potential energy stored in the electrochemical gradient created by another transport process

Why does diffusion alone become inadequate in large, thick organisms?

Diffusion is inefficnet over long distances because interior cells become farther from the external supply of oxygen and nutrients

What is bulk flow, and how does it differ from diffusion?

Bulk flow = movment of a fluid and its dissolved/suspende dmaterials together, driven by a pressure gradient. differs from diffusion in its driving force. Bulk flow transports many different substances simutainiously across a long distance

How do animal circulatory systems and plant vascular systems overcome transport limitations?

Animals - the heart creates pressure differences to encourage bulk flow

Blood transports oxygen, nutrients, signaling molecules, and waste

Plants — xylem and phloem are used to transport water and sugars from roots, to shoots, and between sources and sinks. works on pressure and cohesion-tension

Why is diffusion still needed even when bulk transport systems exist?

Materials still need to cross short distances between transport systems and individual cells (local exchanges)

Why are cell adhesion, specialization, and communication important?

Cell adhesion — maintains tissue structure and mechanical stability

Cell specialization — complex division of labor

Cell communication — coordates growth, metabolism, and responses to environmental changes

What is an alga?

Photosynthetic eukaryotes outside the land plants

Why do algae not form a single evolutionary lineage?

Because of plastic history (secondary endosymbiosis)

Why are cyanobacteria not eukaryotic algae? (4)

• they lack a membrane bound nucleus

• they lack chloroplast

• they have prokaryotic cellular organization

• they do photosynthesis using internal photosynthetic membranes instead of chloroplast

What ecological roles do algae play, including habitat creation by seaweeds? (5)

• primary producers in aquatic ecosystems

• convert CO2 into organic matter

• create physical structures that provide shelter and food

• contribute to global photosynthetic oxygen production

• support aquatic consumers

What are the pigments in green algae

Chlorphyll a, Chlorophyll b

Green plants and green algae belong to the lineage ___

Viridiplantae

Green algae consist of two seperate lineages: ___ and ___. Land plants belong within ___

Chlorophyta and Stretophyta, Stretophyta

Red algae (__) belongs to the ___ super group.

Rhodophtyta, Archeplastida

Pigments for red algae?

Phycoerythrin

Ecological roll of red algae (3)

• build reefs

• food (nori)

• usefull cell-wall materials that we use in labs

Red algae do not have ___ stages in their life cycles. Why is this significant?

Flagellated - significant because it means their sperm cells are genearlly nonmotile and fertilization must depend on water movement or other mechanisms that will bring their gametes together

What is frustule composition

A silica cell wall that has two overlapping halves, like a box and lid, that provide structural protection to diatoms

Ecological importance of diatoms (4)

• major contributors to aquatic primary production

• participate in global carbon cycling

• silical shells contribute to sediment formation after death

• foundation to marine and freshwater foodwebs

Brown algae belong to the group ___

Phaeophyceae

Characteristic pigments of brown algae

Chlorphyll a, Chlorphyll C, and fucoxanthin

What do the holdfast, stipe, and blade do for algae

holdfast - achors to substrate

stipe - supports and connects holdfast to blades

blad - photosynthetic surface

How do dinoflagellates eat

photoautotrphic (obtain energy from light and carbon from Co2)

mixotrophic (some photosynthesize, others feed on prey, some do both)

Ecological importance of dinoflagellates (2)

• live as symbionts in corals

• bioluminescnece

What type of body form is this, what is an example, what are its advantages/limitations

Unicellular - chlamydomonas - efficient exchange because of simple structure, but small overall size

What type of body form is this, what is an example, what are its advantages/limitations

Term

Colonial - volvox - division of labor - requires cell cooperation

What type of body form is this, what is an example, what are its advantages/limitations

Term

Filaments -- spirogyra - large exposed surface - may be vulnerable to fragmentation

What type of body form is this, what is an example, what are its advantages/limitations

Term

Sheets - Ulva - efficnet light absorption and exchange - may be vulnerable to tearing

What type of body form is this, what is an example, what are its advantages/limitations

Term

Differentatied thalli - kelp - different regions perform different functions - greater transport and support requirements.

How do body forms affect material exchange?

Material exchange depends strongly on surface-area-to-volume ratio and diffusion distance

Why does body form not determine sexual life-cycle type?

Body form describes an organism's physical structure, while sexual life-cycle type describes the timing of meiosis, fertilization, and haploid/diploid development

Define haploid, diploid, gamete, spore, and zygote.

haploid - one complete set of chromosomes

diploid - two complete sets of chromosomes

gamete - reproductive cell that fuses with another gamete during fertilization

spore - reproductive cell that can develop without fertilization

zygote - diploid cell produced by the fusion of two haploid gametes

How do mitosis, meiosis, and fertilization affect chromosome number?

Mitosis - produces daughter nuclei with same ploidy as parent nucleus. no affect on chromosome number

n —> n + n

2n —> 2n + 2n

Meiosis - chromosome number is halved

2n —> n

Fertilization - combines two haploid gametes

n + n —> 2n

Explain conjugation and zygospore formation in Spirogyram (7 steps)

1. two haploid filaments allign

2. conjugation tubes form between corresponding cells in the filaments

3. the contents of one cell move through the tube into the other

4. haploid nuclei in the filaments fuse, making a diploid zygote

5. the zygote developes a resistant wall and becomes a zygospore

6. zygospore udergoes meiosis

7. haploid products form new haploid filaments

Spirogrya have a haplontic life cycle

Discuss possible benefits and limitations of predominantly haploid growth.

Benefits: all alleles are expressed because there is only one chromosome set

selection acts directly on recessive alleles,

Limitations: harmful recessive mutations cannot be masked by a second allele

genetic damage may have more immediate consequences

Define diplontic and identify when meiosis occurs.

A diplontic life cycle is one in which the main growing organism is diploid.

The haploid stage (meiosis) is restricted to gametes.

Define haplontic and identify the diploid stage.

A haplontic life cycle is one in which the main growing organism is haploid.

The only diploid stage is typically the zygote.

Explain reproduction in Fucus and the role of conceptacles. (4 steps)

The fucus has a diplontic life cycle

1. diploid adult developes reproductive structures (oogonia that makes eggs, antheridia that makes sperm)

2. Meiosis occurs during gamete production

3. haploid eggs and sperm are released into the surrounding water

4. fertizlation makes a diploid zygote

5. zygote developes via mitosis into a new diploid adult

conceptacles are small cavities in the organism that contain the oogonia or antheridia

Discuss potential benefits and disadvantages of masking recessive alleles in diploids.

Benefits: a function allele can mask a harmful recessive allel in a herterozygote

masking can allow individual carrying that allele to survive and reproduce

Costs: masking makes selection less effective and removing harmful recessive allels, meaning those alleles cna persist and affect offspring that inherit two harmful copies

Define alternation of generations. Distinguish gametophyte and sporophyte.

Alternation of generations is a life cycle in which both haploid and diploid stages undergo multicellular growth.

The two generations are:

• Gametophyte (n): Haploid generation that produces gametes by mitosis.

• Sporophyte (2n): Diploid generation that produces haploid spores by meiosis.

Which generation produces gametes and which produces spores? (Fill out the table)

Discuss potential benefits and costs of having both growing generations.

Fill in the table