Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 107 > Quiz #4 > Flashcards

Quiz #4 Flashcards

1
Q

What are the structures in the endomembrane system?

A 
Nuclear envelope
Endoplasmic reticulum
Vacuoles
Vesicles
Lysosomes
Golgi
Plasma membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are the structures in the endomembrane system related?

A

physical continuity

vesicles that transfer from one to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What structures are not in the endomembrane system?

A

peroxisomes, mitochondria, and chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the nucleus?

A

stores DNA, and is the site of transcription
contains multiple linear chromosomes
outer membrane is continuous with the endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the nuclear envelope?

A

is a double membrane (each membrane is a phospholipid bilayer)
separates the nucleoplasm from the cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are nuclear pores?

A

complexes span both bilayers

regulates movement of substances in and out of nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the nuclear lamina?

A

provides structural support for the nucleus

composed of an immediate filament called lamin, which assembles on the inner surface of the nuclear envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is chromatin?

A

DNA and protein
chromatin can be highly condensed
chromatin becomes even more packaged in mitosis, to prepare for chromatid segregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is DNA packaged?

A

organize the nucleus
protect the DNA from damage
make it easier to move replicated DNA into daughter cell during cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is histone?

A

provides stability and protection to DNA, and it is involved in the packaging of nucleosomes into the 30 nm fibre
4 histone proteins (H2A, H2B, H3, H4) assemble into a larger 8-subunit complex called a histone octamer
DNA + histone octamer = nucleosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the nucleolus?

A

this is a visible sub-compartment of the nucleus (not bound by membrane)
site of the ribosomal RNA (rRNA) synthesis
site of assembly of ribosome protein subunits (each half of the ribosome enters the nucleus separately via nuclear pores)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is 5S RNA is made in the nucleus?

A
  1. Each subunit (made in the cytoplasm) must enter nucleus
  2. Ribosomal subunits associate with 4 different RNA molecules
  3. Final assembly occurs in the cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the endoplasmic reticulum?

A

2 types: smooth and rough
the two types of ER often appear separate, but they are sub-compartments of the same organelle
both types are in plant and animal cells
cells that produce a lot of proteins will tend to have more rough ER
cells that produce a lot of lipids (fats) and steroid hormones will have more smooth ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is rough ER?

A

covered in ribosomes
rER ribosomes are associated with the translation of proteins that are destined for the endomembrane system
site of protein synthesis and assembly
site of protein quality control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are ribosomes?

A

protein factories
particles made of ribosomal RNA and protein
assemble all peptides (using amino acid monomers)
in the cytosol
on the outside of endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is smooth ER?

A

ion storage
phospholipid, steroid synthesis
detox of drugs and alcohol
carbohydrate metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the Golgi apparatus?

A

consists of flattened membranous sacs called cisternae
cis face = “receiving” side of the golgi (faces nucleus)
cisternal maturation: golgi cisternae move in a cis to trans direction
Vesicles form and leave the golgi, carrying products to different membranous organelles, or the plasma membrane
trans face = “shipping” side of the golgi (faces away from the nucleus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of the golgi apparatus?

A

modifies products of the ER
changing carbohydrates on proteins, phospholipids
sorts and packages materials into transport vesicles
it manufactures some macromolecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are lysosomes?

A

is a membranous sac of hydrolytic enzymes that can digest macromolecules
lysosomal enzymes work best in acidic environment inside lysosome
lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids
also important for recycling various structures and organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is autophagy?

A

“self-eating”

the cell eats itself (or parts of itself)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are vacuoles?

A

variable function depending on the cell
food vacuoles: formed by phagocytosis
contractile vacuoles: found in many freshwater protists, pump excess water out of cells
central vacuole: specific organelle of plants, found in many mature plant cells, holds organic compounds and water (helps maintain turgor pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do mitochondria and chloroplasts have in common?

A

both bound by a double membrane
both contain several copies of their own DNA
both contain ribosomes that synthesize a few compounds, but most of the components in each organelle are encoded by genes in the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are perxisomes?

A

also called microbodies
single membrane bound organelles (spherical)
perform reactions (breakdown of molecules or assembly) in which H2O2 (hydrogen peroxide) is a by-product
H2O2 is toxic to the cell
fatty acids + O2 –> smaller products + H2O2 –> H2O + 1/2 O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the functions of the cytoskeleton?

A

gives shape and support to cells (especially in animal cells, no cell wall, and not all cells attach to the ECM
allows cells to change shape (by disassembling in one part of the cell and reassembling in another part)
can act as a system of “cables” throughput the cell
organelles may attach to the cables, and some move along them

25
Q

What are the three types of protein filaments in the cytoskeleton?

A 
microtubules (thick, 25 nm)
intermediate filaments (8-12 nm)
actin filaments (thin, 7 nm)
26
Q

What are microtubules?

A

straight, hollow tubes
walls of the tube are constructed with proteins called tubulins
alpha tubulins and beta tubulins combine to form a dimer
dimers assemble end-to-end into microtubule protofilaments
many protofilaments interact to form tubes
tubulin dimers continue to add to protofilaments, at one end of the tube, termed the plus end
microtubule closes behind the growing tip
when the seam completely closes, the microtubule can either grow again, or start shrinking
microtubules grow and shrink dynamically

27
Q

What are microtubule organizing centers (MTOCs)?

A

in cells, the minus ends of microtubules are anchored in structures called microtubule organizing centers
an organized structure
composed of many different proteins
one of these is another kind of tubulin, gamma tubulin

28
Q

What is a gamma tubulin?

A

forms a stable platform that can be used to start microtubule growth, and it provides an anchor that helps maintain microtubule attachment to the MTOC

29
Q

What is a centrosome?

A

the primary MTOC in most animal cells

30
Q

What are centrioles?

A

small structures at the center of centrosomes
centrioles also have microtubules
arranged around a cylinder composed of other proteins
number and appearance of microtubules can vary, depending on organism and cell type
centrioles are not present in plants and fungi

31
Q

What are microtubule motor proteins?

A

can “walk” along microtubules

two different classes of ATP-driven motors; dynein and kinesin

32
Q

What is dynein?

A

“walks” towards the minus end of the microtubule

33
Q

What is kinesin?

A

“walks” towards the plus end of the microtubule

34
Q

What is the microtubule netowrk?

A

in non-dividing cells, a microtubule network radiates out from the MTOC to provide a basic organization of the cytoplasm, including the positioning of organelles
microtubules grow out from the MTOC to the plasma membrane (minus to plus direction)

35
Q

What is the flagella in eukaryotic cells?

A 
usually only one or, at most, a few per cell
undulating motion (e.g., a sperm tail moves like a corkscrew in 3D, but when it encounters a surface, it slithers like a snake
36
Q

What is cilia?

A

usually present in large numbers on cell surface
they act in unison, like oars
can be used to move the cell, or to move fluids past the membrane
beat using an active power stroke, followed by relaxed recovery stroke

37
Q

What are actin filaments?

A

abundant in all eukaryotic cells
first discovered in skeletal muscle, where actin filaments slide along filaments of myosin to make the cells contract
actin filaments support and strengthen the plasma membrane (from inside the cell)
actin filaments are made of identical actin proteins (actin subunits) arranged in a long chain
like microtubules, actin filaments have a plus and minus end, with more growth occurring at the plus end

38
Q

What structures in the cell are formed from actin filaments?

A

microvilli: apical surface of some epithelial cells
contractile bundles: cell shape
lamellipodia: cell migration
contractile ring: cell division

39
Q

What are intermediate filaments?

A

strong and ropelike
less dynamic than actin filaments or microtubules
do not have a plus/minus end like actin or tubulin
not as dynamic as other filaments (permanent structure)

40
Q

What is metabolism and energy?

A

cells are mini chemical factories, they can perform thousands of reactions
the totality of an organism’s chemical reactions, managing the materials and energy resources of the cell is metabolism

41
Q

What is anabolism?

A

building molecules
requires energy
e.g. synthesis of proteins

42
Q

What is catabolism?

A

breaking down molecules
releases energy
e.g. breakdown of glucose in the presence of oxygen

43
Q

How is energy defined in biochemistry?

A

it is the capacity for change

energy changes are associated with changes in the chemical structures and properties of molecules

44
Q

What is kinetic energy?

A

energy in motion
heat
moving
radiant energy of light

45
Q

What is potential energy?

A

stored energy
chemical energy
concentration gradients
electrical potential

46
Q

What is the First Law of Thermodynamics?

A

energy is never created nor destroyed
the amount of energy in the universe is constant
in a closed system, the quantity of energy does not change, but the energy can flow into different forms

47
Q

What is Gibbs Free Energy?

A

in every energy transfer or transformation, some energy is lost to it’s surroundings (usually as heat)
because energy can be converted into different forms, it is useful to keep track of how much energy is available to do work, termed “free energy”
Gibbs Free Energy (G) is the energy that is available to do work

48
Q

What is the second law of thermodynamics?

A

in a closed system, with multiple energy transformations, free energy (G) decreases and un-useful energy increases
this is referred to as an increase in entropy
every energy transfer or transformation makes the universe more disordered

49
Q

What is entropy?

A

symbolized as S
a measure of disorder in the universe
un-useful energy (energy not available to do work)

50
Q

What is heat?

A

is considered to be the lowest grade of energy
heat increases the random unordered movement of molecules
heat is difficult to store or harness to do work
cannot gather heat from the universe once it has dissipated

51
Q

What is the hydrophobic effect?

A

systems tend towards an increase in entropy

H2O forms a cage around non-polar molecules
the fat limits the ability of some water molecules to bond with other water molecules
more order, lower entropy

putting hydrophobic molecules in the same region limits the restriction on water
less order, higher entropy

52
Q

How do individual reactions in cells follow the Laws of Thermodynamics?

A

systems with high free energy are complex/organized/non-random, and have low entropy
systems with low free energy are disordered/random, and have high entropy (therefore less energy is available for work)

53
Q

What is the change in enthalpy reaction?

A

G = H - TS
change in G = change in H - T*change in S

change in enthalpy is a measure of how much energy is released or absorbed during a chemical reaction

54
Q

What happens when change in G < 0?

A

an exergonic reaction proceeds with a net release of free energy and is spontaneous

55
Q

What happens when change in G > 0?

A

an endergonic reaction absorbs free energy from surroundings and is non-spontaneous

56
Q

How can cell reactions be compared to an isolated hydroelectric system?

A

generator converts energy to electricity only until the system reaches equilibrium
reactions in a closed system eventually reach equilibrium and then do no work
but cells are not in equilibrium, they are open systems experiencing a constant flow of materials

57
Q

How can cell reactions be compared to an open hydroelectric system?

A

intake and outflow keep the system from reaching equilibrium

58
Q

How can cell reactions be compared to an multistep open hydroelectric system?

A

cellular respiration is more similar to this system

equilibrium at each step is never reached, because the products are depleted by the next step

BIOL 107 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions