Biology Midterm

Front 1

diffusion

Back 1

movement of oxygen into cells, movement continues until concentrations are equal,
O2 and CO2 move in and out of cells and organisms via diffusion

Front 2

osmosis

Back 2

movement of water into cells placed into a hypotonic solution

Front 3

transporters

Back 3

only certain solutes are allowed to enter or leave the cell, either through channels or carriers composed of proteins

Front 4

enzymes

Back 4

cells carry out many chemical reactions on the interior surface of the plasma membrane using enzymes attached to the membrane

Front 5

cell-surface receptors

Back 5

membranes are exquisitely sensitive to chemical messages, which are detected by receptor proteins on their surfaces

Front 6

cell-surface identity markers

Back 6

Membranes carry cell-surface markers that identify them to other cells. Most cell types carry their own ID tags, specific combinations of cell-surface proteins and protein complexes such as glycoproteins that are characteristic of that cell type

Front 7

cell-to-cell adhesion proteins

Back 7

cells use specific proteins to glue themselves to one another. some act by forming temporary interactions, and others form a more permanent bond

Front 8

attachments to the cytoskeleton

Back 8

surface proteins that interact with other cells are often anchored to the cytoskeleton by linking proteins

Front 9

hydrophobic

Back 9

domain inserts into lipid bilayer
contains nonpolar amino acid helices or beta-pleated sheets

Front 10

hydrophilic

Back 10

domain is outside lipid bilayer

Front 11

passive transport

Back 11

movement in and out of a cell without energy expenditure by cell,
based on movement of individual molecules,
movement is down or along concentration gradient,
net movement from high to low concentration.

Front 12

channel proteins

Back 12

hydrophilic interior to allow polar molecule movement through aqueous channel,
each channel is specific for one type of ion,
ion channels move cations or anions,
net movement is affected by the concentration gradient, voltage difference across the membrane and if the gate is open or closed

Front 13

carrier proteins

Back 13

move ions and other solutes (ex. sugars, amino acids),
bind do and move molecules in or out of cell,
diffusion is assisted by carrier protein

Front 14

hypotonic

Back 14

lower osmotic (solute) concentration,
loses water

Front 15

hypertonic

Back 15

higher osmotic (solute) concentration,
gains water

Front 16

active transport

Back 16

requires energy expenditure (ATP),
moves molecules against or up concentration gradient,
movement dependent upon membrane proteins,

Front 17

cell respiration

Back 17

to break down glucose and generate energy (ATP)

Front 18

energy is the...

Back 18

capacity to do work

Front 19

potential energy

Back 19

stored energy

Front 20

kinetic energy

Back 20

energy of motion

Front 21

redox reactions

Back 21

coupled oxidation/reduction,
transfer of electrons,
one loses electrons and energy (oxidation),
one gains electrons and energy (reduction)

Front 22

endergonic chemical reaction

Back 22

reaction requires energy input in order to occur
build larger molecules

Front 23

exergonic chemical reaction

Back 23

reaction releases energy when occurs,
break down molecules

Front 24

activation energy

Back 24

energy necessary to "initiate" chemical reactions,
Catalysts lower activation energy needed

Front 25

ATP

Back 25

Adenosine Triphosphate,
energy currency for cell,
supplies energy for nearly all energy-requring processes,

Front 26

ATP hydrolyzed to ADP + Pi to release energy, drives endergonic reactions

Back 26

____

Front 27

enzymes

Back 27

lower activation level of a reaction,
made of a protein or RNA,
name ends in -ase,
catalyze specific reactions,
increase speed of reactions,

Front 28

active site on enzyme does what?

Back 28

binds to substrate

Front 29

what does binding do?

Back 29

changes enzyme shape for better induced fit

Front 30

effect of temperature

Back 30

Increasing the temperature of an uncatalyzed reaction increases its rate because the additional heat increases random molecular movement. This motion can add stress to molecular bonds and affect the activation energy of a reaction.

Front 31

effect of pH

Back 31

ionic interactions between oppositely charged amino acid residues also hold enzymes together. Most enzymes have an optimum pH that usually ranges from pH 6 to 8.

Front 32

ribozymes

Back 32

RNA molecules that can modify molecules (RNA catalysts),
may modify itself,
may modify other molecules

Front 33

cellular metabolism

Back 33

series of chemical steps in biochemical pathways,
each sep controlled by different enzymes

Front 34

effect of inhibitors

Back 34

____

Front 35

metabolism converts PE into ATP

Back 35

___

Front 36

LEO says GER

Back 36

loss of electrons is oxidation
gaining electrons in reduction

Front 37

How do enzymes work?

Back 37

orient substrates into favorable position,
weaken bonds of substrate

Front 38

effect of competitive inhibitors

Back 38

compete with the substrate for the same active site, occupying the active site and thus preventing substrates from binding

Front 39

non-competitive inhibitors

Back 39

bind to the enzyme in a location other than the active site, changing the shape of the enzyme and making it unable to bind to the substrate.

Front 40

ATP is recycled as ADP is recharged

Back 40

___

Front 41

allosteric site

Back 41

most noncompetitive inhibitors bind to a specific portion of the enzyme called the allosteric site. these sites serve as chemical on/off switches

Front 42

allosteric inhibitor

Back 42

a substance that binds to an allosteric site and reduces enzyme activity

Front 43

allosteric activator

Back 43

binds to allosteric sites to keep an enzyme in its active configuration, thereby increasing enzyme activity

Front 44

direct contact

Back 44

membrane to membrane,
tight junctions,
gap junctions,
plasmodesmata

Front 45

paracrine signaling

Back 45

localized signaling,
hormones secreted into circulatory system,
affect distant cells

Front 46

synaptic signaling

Back 46

nervous system,
synapse is junction of nerve cell and target cell,
use neurotransmitters

Front 47

endocrine signaling

Back 47

distance signaling,
hormones secreted into circulatory system,
affect distant cells

Front 48

For autocrine signaling, a cell is sending a signal to ____.

Back 48

itsself

Front 49

synaptic signaling involves what type of cell?

Back 49

nerve cell

Front 50

What are the ligands called for this type of signaling?

Back 50

neurotransmitters

Front 51

what is dephosphorylation?

Back 51

the removal of a phosphate group

Front 52

In which type of signaling do molecules travel long distances?

Back 52

endocrine signaling

Front 53

how far does a paracrine signal travel and is it short or long lived?

Back 53

signals are sent only to neighboring cells within the immediate vicinity of the releasing cell and the signals are short-lived

Front 54

what is a synapse

Back 54

a junction (gap) between 2 neurons or muscle cells,
molecules travel across this gap

Front 55

What does it mean for a chemical reaction to be exergonic?

Back 55

expels energy, leaving the products with less energy than the reactants

Front 56

what are the three steps of cellular respiration?

Back 56

glycolysis, kreb's cycle, electron transport chain

Front 57

what are the inputs of glycolysis?
what are the outputs?

Back 57

inputs: 1 glucose molecule (6 carbons)
2 ATP, 2 NAD+
outputs: 2 pyruvate, 4 ATP, 2 NADH

Front 58

explain what could cause feedback inhibition to occur within the process of glycolysis

Back 58

feedback inhibition could occur if there is already a lot of ATP present. the purpose of glycolysis is to generate ATP, so if a lot of ATP is already present there is no need for the process of glycolysis to continue

Front 59

What serves as the final electron acceptor in aerobic respiration?

Back 59

oxygen

Front 60

What serves as the final electron acceptor in aerobic fermentation?

Back 60

an organic molecule

Front 61

How many carbons does a molecule of oxaloacetate contain?

Back 61

4 carbons

Front 62

how many carbons does an acetyl group have?

Back 62

2 carbons

Front 63

how many NADH, FADH2, and ATP are produced during the Kreb's cycle per 1 molecule of glucose?

Back 63

8 NADH
2 FADH2
2 ATP

Front 64

for the cyclic portion of the Kreb's cycle, what is the beginning and ending molecule? And how many carbons does this molecule have?

Back 64

oxaloacetate, 4 carbons

Front 65

Describe the structure of a phospholipid bilayer, including its hydrophobic and hydrophilic regions

Back 65

2 rows of phospholipids such that their fatty acid tails are faced toward each other and their head portions are facing outward. heads are polar and fatty acid tails are non polar.

Front 66

Which of the three steps of cellular respiration produces carbon dioxide?

Back 66

the kreb's cycle

Front 67

write the complete balanced equation for cellular respiration

Back 67

C6H12O6 + 6O2 yields 6CO2 + 6H2O + energy

Front 68

How many ATP are produced per FADH2 and NADH in the electron transport chain?

Back 68

3 NADH & 2 FADH2

Front 69

under what conditions do yeast produce alcohol instead of using the krebs cycle and electron transport chain?

Back 69

in the absence of oxygen