Exam 2 Flashcards
1
Q
If you separated a plant cell into different components, which component(s) would likely contain the most chromatin?
A
nucleus
2
Q
Which of the following is not part of the endomembrane system of eukaryotes?
A
mitochondria
3
Q
Which of the following is required for a cell to respond to a peptide signal like oxytocin?
A
a membrane bound receptor
4
Q
Which of the following organelles were once independent prokaryote organisms?
A
mitochondria and chloroplast
5
Q
Which of the following is not a function of the cytoskeleton?
a) attach cells to each other
b) hold organelles in position
c) attach cells to the extracellular matrix using membrane proteins
d) assist in transporting vesicles
A
all of these
6
Q
What components of plant cells consist of a double membrane around the inner matrix?
A
mitochondria
7
Q
The microfilaments of the cytoskeleton are primarily composed of:
A
actin
8
Q
A cell structure with an internal cross section showing a characteristic “9 + 2” morphology is the
A
flagellum
9
Q
Compared to eukaryotes, most prokaryotes
A
are smaller
10
Q
Organelles called ribosomes are only found in
A
every cell (prokaryote or eukaryote)
11
Q
Lysosomes are commonly found in animal cells. Based on function, the structure most likely to do the same job in plants is the
A
glyoxysome
12
Q
Elements of a signal transduction pathway must include all but which of these?
a) signals
b) receptors
c) protein kinases
d) changes inside cell
e) response
A
protein kinases
13
Q
Prokaryotic cells are smaller than eukaryotic cells because
A
they do not have internal compartments
14
Q
Which component of eukaryotic cells is a major site of protein synthesis?
A
rough ER
15
Q
In signal transduction, receptors do not
A
bind to many different signals
16
Q
The rough ER is the portion of the ER that
A
has ribosomes attached to it
17
Q
In response to the stress of this test, the steroid hormone cortisol caused your intestine cells to increase fat uptake. If each of your intestine cells turned on different genes in response to cortisol, then the cortisol receptor is probably
A
an intracellular response
18
Q
What is the major distinction between a prokaryotic and a eukaryotic cell?
A
The DNA in prokaryotic cell is not separated from ribosomes
19
Q
The components of the cytoskeleton that shape the nuclear lamina are
A
intermediate filaments
20
Q
In signal transduction, a kinase and a second messenger will
A
amplify the original signal
21
Q
If ________ has occurred, then a message has been transferred across a membrane and when _______ has occurred, then a small amount of a signal created a large response within the cell.
A
signal transduction; signal amplification
22
Q
Which of the following molecules is essential for cell recognition?
A
glycoprotein
23
Q
Which of the following are required for signal transduction to occur?
A
signal, receptor, and response
24
Q
In signal transduction, receptors
A
bind reversibly to the signal
25
The DNA of prokaryotic cells is found in the
nucleoid region
26
What primarily limits the size of cells?
surface area to volume ratio
27
Which of the following organelles is found only in plant cells?
glyoxysome
28
Motor proteins require ATP hydrolysis to function. Therefore, in order for the protein to function
ATP must have water molecule added
29
Which of the following is true about prokaryotes?
they use internal membranes to concentrate reaction
30
A ribosome is a specialized structure but is not considered an organelle because it
is not membrane bound
31
When a chemical signal arrives at a cell from a nearby cell, the chemical signal is called a(n) _____ signal.
paracrine
32
the enzyme alpha-amylase increases rate at which starches broken down by ___ of the reaction
A: lowering activation energy
B: increasing change in entropy
C: decreasing change in free energy
D: increasing change in free energy
E: decreasing equilibrium constant
lowering activation energy
33
in plants, which is not a function of extracellular matrix?
A: supporting cell shape
B: controlling cell volume
C: preventing infection
D: sealing together cells w/in plant tissues
sealing together cells within plant tissues
34
the function of the nuclear pores is to?
regulate movement of materials across nuclear membrane
35
motor proteins interact with which elements of the cytoskeleton?
microtubules
36
what is a false statement about enzymes?
enzymes can convert an endergonic to an exergonic reaction
37
what is a false statement about microfilaments and microtubules?
both are made from same protein monomers
38
redox reactions that convert NADH to NAD+ must?
donate an electron to another molecule
39
where are ribosomes made in eukaryotes and prokaryotes?
eukaryotes: nucleolus
prokaryotes: cytoplasm
40
which of the following interact to generate movement of flagella and cilia?
microtubules and dynein
41
for your eyes to receive light reception, they must rely on ions moving between cells quickly. the best junction for this is ___
gap junction
42
if you isolate a cell that secretes lots of extracellular protein, you hypothesize that this cell has a lot of ___
Golgi
43
which of the three domains of life contain a cell wall?
all of them (Bacteria, Archaea, and Eukaryotes)
44
proteins packaged by Golgi are delivered to the right location by means of?
motor proteins directing the vesicles
45
what is the cell theory and implications?
cells theory: 1) cells are fundamental units of life 2) all cells came from preexisting ones 3) all living things are composed of cells
implication: study of cellular biology is study of life
2) life is continuous 3) origin of life on Earth marked by appearance of first cells
46
what is the difference between cytoplasm and cytosol?
everything in cell besides nucleus is cytoplasm
the fluid stuff in cells is cytosol
47
what are the structures of prokaryotes?
cell membrane, nucleoid (region where DNA located), ribosomes, & cytoplasm
- some have cell wall made of peptidoglycan enclosed by polysaccharide capsule
- flagella (tail that has motor protein) & pili
48
what happens during cell division?
- DNA molecules make chromatin that make chromosomes
- Chromatin attach to nuclear lamina that holds shape of nucleus by holding onto chromatin & nuclear envelope
- Nuclear lamina made form protein, lamina, into intermediate filaments
49
what is the endomembrane system made of?
cell membrane, nuclear envelope, ER, Golgi, lysosomes, and vesicles
50
what does the RER do?
collect newly made proteins (destined for lysosomes, cell membrane, or outside)
modify into their tertiary & tags protein for new location
*most membrane-bound protein made here
51
what does SER do?
modify small toxic molecules (make more polar so easy remove)
site for glycogen degradation & lipid/steroid synthesis and storage of calcium ions (triggers)
52
what is the Golgi's role?
receive protein from ER and sorts/modify/concentrate/package protein for shipment; adds carbs to protein & modifies existing carbs; synthesize polysaccharides for cell wall; cuts large precursor protein to smaller fragments
53
what are the faces of the Golgi?
cis (closest to RER/nucleus); trans (closest to membrane); medial (lies in b/w)
54
where does primary lysosome come from?
come from Golgi & contain digestive enzymes that hydrolyze macromolecules
55
where does secondary lysosomes come from?
when phagosome fuses with primary to form secondary, it spits out useful stuff and the used lysosome exits through exocytosis
56
what are the different plastids?
- chloroplast; made of thylakoid stacks into geranium suspended in stroma
- chromoplasts: store pigments
- leucoplasts: store starch
57
what is peroxisomes do?
accumulate peroxide made by reactions & breaks it down
58
what do glyoxysomes do?
similar to peroxisomes but found only in plants (young ones have a lot) & transforms lipids to carbs
59
what do vacuoles do?
they occur mainly in plants, fungi, and protists and its job is to store, digest, reproduction, and structure
60
what are the components of cytoskeleton (small to big)
1) microfilaments: made of actin that help move entire/part of cell and determine & stabilize cell shape
2) intermediate filaments made of keratin (some) and anchor cell structures in place & resist tension- doesn't continually break and form
3) microtubules: form rigid internal skeleton and make framework for motor protein
61
where do motor proteins move?
kinesin move toward + end and dyne's move toward - end
62
what shape does flagella have and how does it move?
microtubules has a 9+2 array (9 fused outside and 2 unfused inside)
movement is permitted by dynein (move past each other) & nexin (bending)
63
what is the animal's extracellular made of?
fibrous protein (collagen- 25% protein in body), glycoprotein called proteoglycans, & third substance binding the other two
64
what is the function of the plant cell wall (plant's extracellular material)
structure, prevent infection, and growing as cell grows
65
what is metabolism?
sum total of all chemical reactions occurring
66
what is the 1st and 2nd law of thermodynamics?
1st law: energy is neither created nor destroyed
2nd law: disorder tends to increase & entropy is the measure of disorder in a system
67
what is the equation for total energy and how does delta G correlate?
enthalpy (H): total energy & free energy (G)
negative delta G: energy released and positive delta G: energy consumed
68
what is the formation and hydrolysis of ATP called?
energy-coupling reaction
69
what is 2 reasons why ATP is used?
1. b/c phosphate groups are neg, it takes lots of energy for form covalent bonds (energy stored there)
2. energy in P-O bond (phosphoanhydride) much higher than O-H bond
70
A photosystem is
an integral membrane protein with many pigment molecules
71
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.
72
_______ is a 5-carbon molecule that is recycled to fix CO2 in the carbon cycle.
RuBP
73
what does a more negative delta G mean?
spontaneous
74
what starts a reaction and what does enzymes do in it?
activation (Ea) starts the reaction & enzymes lower it
75
what is oxidoreductases do?
transfer electron molecule molecules (energy metabolism)
76
what do transferases do?
transfer groups of atoms (functional groups) between molecules
77
what do hydrolases do?
adds water to covalent bonds to break
78
what do lyases do?
catalyze non-hydrolytic bonds
79
what do isomerases do?
move functional group from one place to another in one molecule
80
what are ways enzymes lower Ea?
1. substrate orientation (making sure substrates are orientated right)
2. putting strain on bond
3. adding chemical group (side chain of enzyme's amino acids)
81
how does adding a chemical group lower Ea?
- acid base catalyst: acidic/basic R group transfer H+ atom to/from substrate
- covalent catalyst: function group in R group forms temporary covalent bond
- metal ion catalyst: metal ions bound to side chains can lose/gain electrons
82
some enzymes need a partner so what can be a partner?
- prosthetic group (non amino acids partners permanently bound to enzymes)
- inorganic cofactors
- coenzymes (non protein carbon containing)
83
what is irreversible inhibition?
when inhibitor covalently bonds to certain R groups of enzymes, permanently shutting it down
84
what are the types of reversible inhibitor?
- competitive inhibitor: similar to substrate to bind to active site and enzyme can't work
- uncompetitive inhibitor: binding to enzyme-substrate complex, preventing release of product
- noncompetitive inhibitor: bind to site different from active site
85
what are allosteric enzymes?
quaternary proteins that can be controlled via changes in shape with many active sites (get ball rolling)
- Polypeptides with active sites called catalytic subunit & allosteric sites called regulatory subunits
86
what does glycolysis forms?
2 pyruvate, 2 ATP, and 2 NADH
87
what does pyruvate oxidation do?
pyruvate oxidizes to form 2 carbon acetate which combines with coenzyme A to form two acetyl coA & two NADH & 2 CO2 (one for each)
88
what happens in the Kreb cycle?
acetyl coA donates acetyl group to 4 carbon compound (oxaloacetate) to form 6 carbon citrate
- input are acetate, water, GDP, NAD+, & FAD
- output are CO2, NADH, FADH2, and GTP
89
what does GTP do & final products of Kreb cycle?
GTP combines with ATP to form GDP and ATP
final products are 4 CO2, 6 NADH, 2 FADH2, and 2 ATP
90
what are the 2 steps of oxidation phosphorylation?
1. electron transport: electron from NADH & FADH2 pass through respiratory chain (series of membrane associated electron carrier) creates proton gradient
2. chemiosmosis: proton diffuse through channel protein (ATP synthase)
91
what is the parts of respiratory chain?
- NADH passes e- to complex I (NADH-A reductase) which passes to Q
- Complex II passes e- from FADH2 to Q
- Complex III (cytochrome reductase) receive e- from Q and give to cytochrome C
- cytochrome C receive from III & passes to IV (cytochrome C oxidase) which passes to O2 forming H2O
92
what is a photosystem?
pigment has magnesium center & hydrocarbon tail that anchors chlorophyll to other protein. energy released by other pigments bounce until it hits chlorophyll a @ reaction center, which gives up e- to NADP+ to reduce it
93
what is the difference between noncyclic and cyclic?
- noncyclic generates ATP & NADPH but not enough ATP (photosystem I & II)- starts with oxidizing H2O
- cyclic recycles the e- so enough ATP is produced (photosystem I)
94
what are the phases of Calvin cycle?
1. fixation of CO2 (carbon in CO2 added to RuBP to make six carbon, which is catalyzed by rubisco & immediately broken down to 3PG
2. reduction of 3PG. reduced to form G3P, which involves phosphorylation of ATP & oxidation of NADPH
3. regeneration of RuBP: most G3P end up as RuMP & ATP turns into RuBP
95
what are the different types of signals?
autocrine: diffuse to & affect the cells that make them
juxtacrine: affect only cells right next to & in contact with signaling cells
paracrine: diffuse to & affect nearby cells
96
what do ligands do?
ligands are specific chemical signal molecule that fits 3D site of receptor, causing it to change shape
97
what are agonists?
chemical that sets off receptor like original ligand does
98
what are antagonists?
inhibitor that bind to receptor but doesn't set it off
