BIO Exam 2

In what ways can enzymes lower activation change?

• By inducing physical strain on the substrates.

• By orienting two substrates so they can react more easily.

• By adding charges to the substrate.

reversible competitive inhibitor

Forms non-covalent attachment to the enzyme

at the active site

reversible non-competitive inhibitor

Binds to the enzyme away from the active site

irreversible inhibitor

Forms covalent attachment to the enzyme

allosteric activator

Stabilizes the enzyme in active conformation

feedback inhibitor

Involves an end product binding to an enzyme

at the front of the pathway

An enzyme is said to be ________ when the rate of product formation is maximal. The only

way to increase the rate of product formation is to _________ and __________

saturated; synthesize new enzymes; activate already present enzyme molecules

uniporter

carries one specific ion or molecule

antiporter

carries two different ions or molecules, but in different directions.

symporter

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

What are the steps for Na+/K+ ATPase pump?

1. Three Na+ ions and 1 ATP binds to the pump.

2. ATP is hydrolyzed to ADP.

3. The pump is phosphorylated, causing Na+ ions to leave the pump.

4. Two K+ ions bind to the pump.

5. The pump is dephosphorylated, causing K+ ions to leave the pump.

Diffusion

Net movement of particles from areas of high to low concentrations

Equilibrium

Equal concentrations across the membrane barrier

Osmosis

Passive movement of water across a membrane

Osmotic pressure

Force applied to a solution to prevent osmosis

Osmolarity

Total number of solute particles per liter of water

What are the two major membrane proteins involved in facilitated diffusion?

Channels and Carriers

What kind of bonds does NaCl contain?

ionic

What kind of bonds does N2 contain?

non-polar covalent

What kind of bonds does H2O contain?

polar covalent

What kind of bonds does CH4 contain?

non-polar covalent

Phagocytosis

cellular eating

Pinocytosis

cellular drinking

Exocytosis

Secretion of materials outside cell.

Receptor-mediated endocytosis

Intake of specific molecules into cell.

Mitochondria

Produce ATP

Golgi apparatus

Process and package materials for secretion

Rough ER

Synthesize protein and adds carbohydrates to proteins

Lysosome

Carry out digestion and autophagy

Peroxisome

break down toxic peroxide compounds

What are the three differences between plant and animal cells?

Animal cells:

• centrosomes (centrioles)

• lysosomes

• small vacuoles

Plant cells:

• cell wall

• chloroplast

• large central vacuoles

Cyanobacteria contain ________ and are therefore _______ . Archaea are mostly found in

______ and have the characteristics of _________

chlorophyll; autotrophs; extreme conditions; both bacteria and eukaryotes

____ does not permit movement of any materials between cells. _____may permit some

material movement while ______ allows ions and small molecules to pass through.

Tight junctions; desmosomes; gap junctions

what protein is present in microfilaments and can its monomers be removed?

Actin; yes

what protein is present in Intermediate filaments and can its monomers be removed?

Keratin; no

what protein is present in microtubules and can its monomers be removed?

Tubulin; yes

What are the steps for the ligand-gated ion channels?

1. Neurotransmitter binds to its appropriate receptor.

2. The receptor changes shape and opens.

3. Ions flow into the cell

4. The cell responds

What are the steps for the G protein-coupled receptors (GPCRs)?

1. The signal binds to the GPCR, changing the conformation of the receptor.

2. The alpha subunit of the G protein replaces GDP with GTP

3. The alpha subunit of the G protein dissociates.

4. The alpha subunit of the G protein activates an effector protein.

What enzyme is involved in the addition of phosphate groups?

kinase

What enzyme is involved in the removal of phosphate groups?

phosphatase

What enzyme is involved in the generation of cyclic AMP?

adenylyl cyclase

What enzyme is involved in the cessation of cyclic AMP activity (by conversion to AMP)?

phosphodiesterase

Removal of phosphate molecule activates an enzyme while addition of phosphate molecule inactivates an enzyme. True or False?

false

Prokaryotes contain membrane-bound organelles. True or False?

False

Cells prefer a larger surface area-to-volume ratio because it helps maintain the cell’s

metabolic activity through efficient transport of materials into and out of cell. True or False?

True

cellular respiration

process through which cells break down food to make energy

ATP

energy currency of the cell

what happens when ATP goes through hydrolysis?

phosphate groups release energy

NAD

• electron carrier

• can be easily reduced/oxidized

• less stable

• reduced form: accepts electrons

• oxidized form: lost electrons

oxidation-reduction reaction

don’t occur in isolation

FAD

electron carrier

what are the steps for Cellular Respiration?

1. glycolysis

2. oxidation of pyruvate

3. citric acid cycle

4. electron transport chain

glycolysis

cells break down glucose to make pyruvate and release energy

pyruvate

acetyl-CoA after decarboxylated and oxidized

citric acid cycle

cells break down acetyl-CoA to release energy and produce CO2; occurs in mitochondrial matrix; requires oxygen indirectly

electron transport chain

cell uses high-energy electrons from NADH & FADH2 to produce large amounts of energy; occurs in inner mitochondrial membrane; require oxygen directly

photosynthesis

process that captures energy from sunlight and converts it to carbs

communication

between cells and the environment is critical to function life

intracellular signaling

communication within a cell

intercellular signaling

communication between cells

ligands

small molecules that serve as chemical signals; released by a signaling cell

• interaction is like lock (receptor) and key (ligand)

autocrine

fast; apoptosis and stimulation of response in immune cells

gap junctions

fastest; small molecules/ions diffuse vis cytoplasm; heart contractions

paracrine

fast; neutral signaling and wound healing

non-polar ligands

diffuse through plasma membrane; interact with intracellular receptors

polar ligands

bind to extracellular domain of cell-surface receptors