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52 Cards in this Set

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  • Back
What is metabolism?
All the chemical reactions that cells in living organisms do that are necessary for the maintenance of life
What is a metabolic pathway?
An enzyme-mediated sequence of reactions in cells
What is the role of enxymes in all metabolic pathways in organisms?
Helper for reactant
What is the substrate, intermediates, and product of metabolic pathways?
The substrate is the starting substance, the intermediate is the substances formed during a reaction sequence, the products are what is left at the end.
How does an enzyme work?
They lower the activation energy needed for reactions to start.
What does it do in the metabolic pathway?
It brings a substrate/reactants to a transition state.
What is the 'transition state' of metabolic reactions?
When molecules are in position for a collision causing a successful reaction.
What does it mean that enzymes are specific?
Each type of enzyme recognizes and binds to only certain substrates.
What are the factors that influence enzyme activity?
Salt concentration
Allosteric Regulators
Coenzymes and Cofactors
What is the effect of temperature on enzyme activity?
Small increases in temp. increase collisions/rx rates.

Very high/low temps disrupt bonds/destroy shape of activation sites
What is the effect of salinity on enzyme activity?
Too much or too little salt interferes with the hydrogen bonds that help hold an enzyme in its three-dimensional shape, inactivating the enzyme
What are co-enzymes?
Small molecule that participates in an enzymatic reaction and is reversibly modified during the reaction. Made from organic compounds that accept electron and hydrogen ions and transfer them within the cell.
What are co-factors?
Co-factors, like co-enzymes, help out at the enzymatic reactions. Are inorganic molecules like metal ions.
What is an allosteric activator/inhibitor?
A molecule that binds to the enzyme on another area than the active site and functions to change the enzyme's shape in a way that allows or prevents a reaction.
Describe feedback inhibition.
A change that results from a specific activity during metabolic reaction that shuts down the activity.
What is the chemical that carries energy in organism's cells? How is energy carried in this chemical?
ATP is the main energy carrier. It couples energy-releasing and energy-requiring reactants. ATP primes molecules to react by transferring a phosphate group to them.
What is a concentration gradient and what does it mean for a molecule to travel down it?
Means the number of molecules or ions in one region is different than the number in another region. Substances move from more concentrated to less (down gradient) if there are no other forces.
What factors influence diffusion and how do they affect diffusion?
Steepness of concentration gradient: the steeper, the faster

Molecular Size: the smaller, the faster

Temperature: The higher, the faster

Electrical or pressure gradients: diff. in elect. charge, diff. in exerted force
What is a solution, solute, and solvent?
Solution: combination of two substances in which molecules of each are equally disbursed.

Solute: substance being dissolved

Solvent: substance doing the dissolving
What are 5 ways molecules can get into or out of a cell through the plasma membrane?
Diffusion across the lipid bilayer

Passive (facilitated) transport

Active transport (uses ATP)


What is osmosis?
A special kind of diffusion, of water across a selectively permeable membrane. The side with the most solute molecules has the lowest water concentration.
Define tonicity, hypertonic, isotonic, and hypotonic.
Tonicity: relative solute concentration of two fluids

Hyper: having more solutes
Iso: having same amount
Hypo: having fewer solutes
What molecules easily diffuse through cell membranes?
h20, O2, CO2
What do we call the molecule that makes passive transport possible?
Channel protein/Passive transport protein
What is facilitated passive transport?
Transport through proteins that are gates and need to be facilitated to open
What three things facilitate passive transport?
Ligand (something that binds to the protein)

Mechanical means, such as sound waves

Electrical stimulation, or change in charge of molecules in membrane
Why is energy needed in active transport? What kind?
Because it is diffusion of a solute against the concentration gradient. ATP!
What is teh difference between endocytosis and exocytosis? What is phagocytosis?
Exo: Cytoplasm vesicle fuses with teh plasma membrane and contents released outside cell

Endo: Plasma membrane sinks inward, seals back on itself, forms vesicle inside the cytoplasm

Phago: Encocytosis in amoeba and macrophages, microfilaments move cytoplasm into a pseudopodia which surrounds what is to be taken in.
What is the ultimate energy source for organisms on earth? What is the name for the process of converting it into usable energy for living things on earth?
Sunlight. Photosynthesis.
What is the chemical equation for photosynthesis? What are the reactants and the products?
Water and carbon dioxide
---light energy--->
Oxygen, glucose, water
In what kind of an organism does photosynthesis take place?

Plants, many protists, some bacteria.
What light waves or photons are useful in photosynthesis?
Violet (380 nm) to red (750 nm)
What pigments are necessary for photosynthesis?
Clorophyll a and b, carotenoids, xanthophylls, phycobilins
What are the 2 reactions of the photosynthetic process called? Where does each take place?
light dependent and light independent.

Light dependent take place in the thylakoid membranes of the chloroplast in a eukaryotic organism and in the cell membrane of a prokaryote

Light independent take place in the stroma
What is a photosystem? Where are they located?
A cluster of 200-300 pigments and other molecules that trap energy from the sun. Located in the thylakoid.
What are the two products of light reactions?
What are the products of light independent reactions? What is the biochemical pathway called that produces this? What is needed for this reaction?
Glucose, ADP, NADP+. Calvin-Benson cycle.
Carbon dioxide, ATP, NADPH.
How are photosynthesis and cellular respiration related?
Photosynthesis is energy-storing, while CR is energy-releasing pathway. Photos. releases oxygen, CR requires it. Phots. requires carbon dioxide, CR releases it.
What do we call the process that organisms use to get energy? What kind of energy does a cell use? Where is the energy found in food?
Cellular respiration. A cell uses food to get energy. Glucose.
What is the chemical equation for cellular respiration? What are the reactants and products?
Glucose + Oxygen


Carbon dioxide + Water
In what organisms does cellular respiration take place? In what organelle does this take place in eukaryotes? In prokaryotes?
IN the cells of all organisms, in the cytoplasm and mitochondria.
Where are the three stages of cellular respiration and how many ATPs are made at each stage?
stage 1: glycolysis. 2ATP. cytoplasm.

stage 2: krebs cycle/prepping. 2ATP. mitochondria.

stage 3: electron transport chain. 32ATP. mitochondria.
How much ATP does anaerobic or aerobic respiration create?
anaerobic makes 2, while aerobic makes 36 or more
What coenzymes are needed for cellular respiration? And from what vitamins are they derived
NAD+, Niacin. FAD, B12.
By what process are ATPs made in glycolysis and Krebs cycle? In the electron transport chain?
In glycolysis and krebs cycle, at substrate-level phosphorylation. oxidative phosphorylation is the last.
How does substrate-level phosphorylation make ATP? How about oxidative phosphoylation?
First, means a substrate moleculte donates its phosphate group. And the second is the process of actively pumping hydrogen ions across the selectively permeable membrane.
What is ATP synthase?
A special transport protein that allows hydrogen ions to pass through.
What is the role of oxygen in cell respiration?
The final electron acceptor which then combines with H+ to form water. Electron transfer requires the presence of oxygen, otherwise the chain will get oxidized and stop accepting electrons.
Name the poisons that interfere with electron transport and HOW they interfere with the process.
cyanide and carbon monoxide bind with an electron carrier in the third protein complex. They block off the passage of electrons to oxygen.
What is fermentation?
Making ATP in conditions without oxygen.
What 2 kinds of fermentation are there and what is the difference in resulting products and mechanisms?
Alcoholic and lactate fermentation!
What is the total energy harvest in cell respiration?
36 ATP