BIOL 111 Fletcher TAMU EXAM 2

intergeral proteins

a protein imbedded into membrane structure

peripheral proteins

bound to the surface of the membrane, polar

Gylcoprotiens

which contain oligosaccharide chains (glycans) covalently attached to amino acid side-chains

globular proteins

spherical, water-soluble proteins.

Viral receptors on the cell surface:

Can bind directly to icosahedral virus capsid proteins

Interact with glycoproteins of enveloped viruses

Can be carbohydrate or protein molecules

Have cellular functions

alpha helix

A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure.

Hypertonic

Having a higher concentration of solute than another solution.

isotonic

Having the same solute concentration as another solution.

Hypotonic

Having a lower concentration of solute than another solution

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

channel transport proteins

Form channels with central pores

Allow specific molecules to pass

Each channel specific for a certain molecule

carrier proteins

bind to molecules and change shape to shuttle them across the membrane

Aquaporins

water channel proteins

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

Uniporter

A carrier protein that transports a single molecule across the plasma membrane.

symporter

transporter that carries two different ions or small molecules, both in the same direction

antiporter

A carrier protein that transports two molecules acrss the plasma membrane in opposite directions.

electrical chemical gradient

gradient of ions across a membrane

electrogenic pump

a transport protein that generates voltage across a membrane

secondary active transport

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport.

bulk transport

The process by which large particles and macromolecules are transported through plasma membranes. Inc. exocytosis and endocytosis

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

Exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

increasing rate of diffusion

Na

sodium-potassium pump

Na-> in

K+->out

Metabolism

transform matter and energy

metabolic pathways are

cellular respiration

catabolic pathways

Metabolic pathways that release energy by breaking down complex molecules into simpler compounds.

cellular respiration

Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

potential energy

stored energy that results from the position or shape of an object

kentic energy

the energy an object has due to its motion

free energy

energy that is available to do work

exergonic reaction

A spontaneous chemical reaction in which there is a net release of free energy.

endergonic reaction

A non-spontaneous chemical reaction in which free energy is absorbed from the surroundings.

first law of thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Anabolic

A process in which large molecules are built from small molecules

Entropy

A measure of disorder or randomness.

ATP

energy

Enzymes

lower activation energy

inhibition

negative

activation

positive

alosteric site

This area is located on the enzyme where drugs attach to.

competitive inhibition

substance that resembles the normal substrate competes with the substrate for the active site

noncompetitive inhibitor

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.

feedback inhibition

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

Glycolysis

the breakdown of glucose by enzymes, releasing energy and pyruvic acid.

Glycolysis inputs

glucose, 2 ATP, 2 NAD+

glycolysis output

2 pyruvate, 4 ATP, 2 NADH

Kinase

an enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule.

isomerases

Transfer of groups within molecules to yield isomeric forms

aerobic respiration

Respiration that requires oxygen

pyruvate oxidation

Conversion of pyruvate to acetyl CoA and CO2 that occurs in the mitochondrial matrix in the presence of O2.

citric acid cycle

Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.

Oxaloacetate

A four-carbon molecule that binds with the two-carbon acetyl unit of acetyl-CoA to form citric acid in the first step of the Krebs cycle.

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

anaerobic metabolism

The metabolism that takes place in the absence of oxygen; the principle product is lactic acid.

lactic acid fermentation

the chemical breakdown of carbohydrates that produces lactic acid as the main end product

alcohol fermentation equation

pyruvic acid + NADH → alcohol + CO₂ + NAD⁺

final electron acceptor of ETC

Oxygen

final electron acceptor of lactic acid

pyruvate is last electron acceptor

Warburg effect

cancer cells preferentially use glycolysis while decreasing oxidative phosphorylation

nerve synapse

gap between nerve cells

ATP synthase

Large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

Autotroph

An organism that makes its own food

Photoautotrophs

Organisms that use light as a source of energy to synthesize organic substances.

Chemoautotrophs

Organisms that use hydrogen sulfide or other chemicals as energy source instead of light.

lumen

where photosynthesis happens

Chloroplast

An organelle found in plant and algae cells where photosynthesis occurs

Heterotroph

An organism that cannot make its own food.

light reactions

The first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.

thylakoid membrane

membrane in a chloroplast where the light reactions of photosynthesis occur

Stroma

The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

inner thylakoid space

where H+ ions build up during photosynthesis

Grana

the stacks of thylakoids embedded in the stroma of a chloroplast.

grana (granum)

splits water

produces ATP

Forms NADH

releases oxegyen

Calvin Cylce

light-independent reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugar

calvin cylce carbon fixation

catalyzes reaction of CO2 and RuBP into 2 molecules

Calvin cylce: reduction

ATP and NADH are used to convert the 2 molecules of 3-PGA into 2 molecules of PGA, these gain electrons. Overall, 5G3P are regulated into Ru BP

Calvin cylce: regeneration

5-G3P molecules remain in the cycle and are used prepare for more CO2 to be fixed

During fixation

9 ATP are converted to ADP (6 during fixation and 3 during regeneration

during reduction

6 NADPH are converted to NAD+