BISC 130 Exam 2

what is the plasma membrane best described as?

fluid mosaic model

what are the components of the plasma membrane?

phospholipids, steroids (cholesterol), proteins (integral), carbohydrates (glycolipids, glycoproteins)

why is the plasma membrane fluid?

lipids and proteins are not covalently attached to each other

what can affect fluidity?

temperature and lipid composition

what is diffusion?

solutes move from high to lower concentration

what is passive transport?

free, doesn’t need energy to disperse

the plasma membrane is ______________

selectively permeable

what is facilitated transport?

materials move down concentration gradient, high to low

channel proteins

have a hollow core; are always open

carrier proteins

fit around substances by changing its shape;

_______ are faster than _________

channel; carriers

what are aquaporins?

they allow water to enter and exit the cell at a high rate; are always open

are sodium channels always open?

no

what is osmosis?

transport of water through semipermeable membrane, no solute allowed to pass through, passive transport

how does water move in osmosis?

from low solute concentration to higher

movement depends on _________

tonicity

what is tonicity?

amount of solute in a concentration

what is a hypertonic solution?

cells shrinks; water exits the cell; bad for cells

what is a hypotonic solution?

cells swell; water enters cell; good for plant cells, bad for animal cells

what is an isotonic solution?

cell conditions are the same inside and outside of the cell; good for animal cell, bad for plant cell

active transport

moves materials against concentration gradient, requires energy

how does active transfer move?

low to high concentration

what are the two types of bulk transport?

endocytosis and exocytosis

bulk transport

active transport of large structures or quantities

what does endocytosis do?

move particles into the cell

what are the two parts of endocytosis and what do they carry?

phagocytosis: larger particles, pinocytosis: smaller particles

what are the two types of energy?

potential and kinetic energy

what does potential energy include?

chemical energy that when broken releases energy

what is the first law of thermodynamics?

energy cannot be created or destroyed

energy can be ________ from one form to another

converted

what is free energy?

the energy available to do work, energy in a system is quantified as this

what are the 2 types of chemical reactions?

exergonic and endergonic

what is an exergonic reaction?

high to low energy production, products are at lower energy than reactants

what do exergonic reactions do?

they destroy

what is a endergonic reaction?

low to high energy production, products are at a higher energy than reactions

what do endergonic reactions do?

they build

what do reactions need to overcome to proceed?

activation energy

what is heat and what can it do?

a form of energy, it can be used to overcome activation energy

heat is not feasible in ______

cells

activation energy can be lowered by

catalysts

what do catalysts do?

hold reactants and strain chemical bonds to lower activation energy

what are most catalysis and what are they called?

proteins and are called enzymes

what forms enzyme-substrate complex

substrates bind at the enzyme’s active site

enzymes are very specific for their _________

substrates

what is induced fit?

enzymes change their shape to fit substrates

after the reaction occurs _____________

the enzyme assumes original shape, and is free to work again

what are the two types of enzyme inhibitors?

competitive inhibition, allosteric inhibition

what does competitive inhibition do?

they block the active site

what does allosteric inhibition do?

changes the shape of enzymes

allosteric activators

they bind away from the active site and increase the enzyme function, make it a better shape for binding substrate

some enzymes require ________ and/or _______to function

cofactors; coenzymes

what are cofactors?

inorganic ion; iron and magnesium iona

what are coenzymes?

small organic molecules; vitamins

what makes up metabolism?

anabolic and catabolic

what does anabolic do?

it builds pathways that require energy input

what does catabolic do?

releases energy, breaks down molecules

what are metabolic pathways regulated by?

feedback inhibition

what is feedback inhibition?

a products effect of a reaction sequence to decrease its further production by inhibiting the first enzyme’s activity in the pathway that produces it

what is the problem with ATP?

it is unstable and short term

loss of electrons=

oxidation

Gain of electrons=

reduction

electrons have ________ energy

potential

losing electrons _____ energy

lower

oxidation and reduction form

redox reductions

C₆H₁₂O₆+O₂

CO₂+ H₂O+ energy ATP

what are the stages of cellular respiration?

glycolysis, pyruvate oxidation, the citric acid cycle, electron transport chain, ATP synthase

what does glycolysis do?

it is an anaerobic 10 enzyme metabolic pathway process, it takes glucose (6-carbon) and turns it into pyruvate (3-carbon)x2, ATP and NAD+ are broken down, takes place in the cytoplasm, substrate level phosphorylation

what does ATP break down into?

ATP-> ADP+ P_i

what does NAD+ break down into?

NAD⁺ reduced to NADH

what does pyruvate oxidation do?

pyruvate is broken down, oxidized, and attached to CoenzymeA (CoA), releases CO2, generates NADH, and results in Acetyl-CoA

what happens in the Citric Acid Cycle?

acetyl group (2-carbon) is paired with oxaloacetate (4-carbon) to form citrate (6-carbon), citrate is then broken down throughout the cycle back into oxaloacetate, CO2 is released, NADH and ATP are generated, FAD is reduced to FADH2

What happens in the Electron Transport Chain?

NADH and FADH2 are oxidized into NAD+ and FAD, electrons are passed through e-carriers, creates O2 and H2O, active transport pumps H+ across the membrane, creates a proton gradient

what happens with each transfer in the ETC?

electrons lose energy

what happens in ATP synthase?

a large multiprotein complex that spans the membrane, responsible for chemiosmosis, allows H+ to pass through, generates ATP, oxidative phosphorylation, aerobic respiration

what is chemiosmosis?

process were there is a production of ATP in cellular metabolism by the involvement of a proton gradient across the membrane

oxidative phosphorylation

production of ATP using the process of chemiosmosis in the presence of oxygen

aerobic respiration

process where organisms convert energy in the presence of oxygen

anaerobic respiration

process where organisms convert energy in the absence of oxygen

fermentation

process of regenerating NAD+ with either an inorganic or organic compound serving as the final electron acceptor in the absence of oxygen

what is the problem with fermentation, why?

accumulation of NADH, because no ETC

what is the solution to fermentation’s problem?

reducing an organic molecule

what is an example of fermentation?

lactic acid and ethanol fermentation

catabolism of other carbohydrates

broken into monosaccharides, then enter glycolysis

catabolism of proteins

broken down into amino acids, enter glycolysis, pyruvate oxidation, or citric acid cycle

catabolism of lipids and fatty acids

broken down into two carbon units, converted to acetate, enters citric acid cycle

heterotrophs

organisms that consume organic substances or other organisms for food

autotrophs

organism that gets carbon from inorganic sources

photoautotrophs

organisms capable of producing its own organic compounds from inorganic sources and utilizing energy from sunlight

autotrophs provide _____________ for heterotrophs

food (organic compounds)

in eukaryotes photosynthesis takes place in ________

chloroplast

thylakoids increase __________

surface area

photosynthesis

CO₂ + H₂O + light energy-> C₆H₁₂O₆ (glucose) + O₂ (gas)

what are the two parts of photosynthesis?

light dependent reactions, light independent reactions,

light is a type of _______________

electromagnetic radiation

what characteristics does light have?

specific wavelength (different colors do too), a wave nature and particle nature

what do particles called photons do?

carry energy

what is pigment?

chlorophylls and carotenoids

what photosystem is the LDR?

photosystem II

what happens in the LDR?

photons strike pigments exciting electrons in the chlorophyll to a high energy state, high energy excites reaction center chlorophyll, RC chlorophyll delivers its high energy through ETC, low energy electrons arrive at photosystem I’s RC chlorophyll, NADP+ to NADPH

what happens in the LIR steps 1-3?

enzyme: rubisco preforms carbon fixation by attaching CO2 to ribulose biphosphate (5-carbon)- creating 3-phosphoglyceric acid (3-PGA, 3-carbon)x2, spends ATP and NADPH used to reduce 3-PGA to glyceraldehyde 3-phosphate (G3P, 3-carbon), ATP used to regenerate ribulose biphosphate