Principles of Biology (Exam 2) Flashcards
1
Q
Phospholipid bilayers are ____permeable
A
semipermeable
2
Q
within the phospholipid bilayer, the heads are ____ while the tails are ____
A
heads are hydrophilic, tails are hydrophobic
3
Q
what is amphipathic
A
molecules containing hydrophobic AND hydrophilic regions
4
Q
What substances CAN move through the phospholipid bilayer
A
small, nonpolar molecules. Oxegyn, carbon dioxide, some water molecules
5
Q
what substances CAN NOT move through the phospholipid bilayer
A
large, polar, water-soluble molecules; glucose, ions (H+, Na+, K+, etc.)
6
Q
What are the tranposrt proteins that assist hydrophobic molecules through the phospholipd bilayer
A
channel proteins (for water: aquaporins, for ions: Ion Channels) and carrier proteins
7
Q
define channel proteins (what are the two)
A
provide corridors that allow a specific molecule or ion to cross the membrane. Aquaporins, Ion channels
8
Q
define carrier proteins
A
they undergo a subtle change in shape that translocates the solute-binding site across the membrane
9
Q
What is diffusion
A
water moves from higher to lower concentration (greater the difference in concentrations, the greater the rate of diffusion; higher temperature does the same)
10
Q
what is passive transport
A
11
Q
What are the transport proteins that assist hydrophobic molecules through the phospholipid bilayer
A
channel(for water: aquaporon) and carrier proteins (
12
Q
what is active transport (give ex)
A
requires energy (in form of ATP)
EX: Sodium potassium pump
13
Q
what is osmosis and what are the 3 types
A
the movement of water from lower to higher concentration of a solution; hypertonic, hypotonic, isotonic
14
Q
what is hypertonic
A
has higher concentration of solution; water will move towards it
15
Q
what is hypotonic
A
lower concentration of solution; water will move away from it
16
Q
what is isotonic
A
17
Q
which organelle(s) in plant cells deals within maintaining turgid pressure
A
the vacuole and cell wall
18
Q
plasmolysis
A
when the plant cell shrivels up
19
Q
facilitated diffusion
A
specific proteins facilitate the passive transport of water and select solutes
20
Q
what is co-transport
A
ATP powered pump + channel or carrier proteins, active transport + passive transport… ATP makes more efficient
21
Q
what is endocytosis and the 2 types
A
importation of larger particles into the cell; phagocytosis and pinocytosis
22
Q
what is exocytosis
A
things losing out of the cell… the cell releasing waste
23
Q
what is phagocytosis
A
cell “eating”; bringing in whole particles
24
Q
pinocytosis
A
cell “drinking”; absorbing liquids
25
plant cells become ____ in a isotonic solution
flacid
26
we want blood cells to remain _____
isotonic
27
what are the two types of energy
kinetic energy and potential energy
28
what is kinetic energy
the energy of movement (eg. light, heat, electricity, moving objects)
29
what is potential energy
stored energy (eg. chemical energy in bonds, battery, membrane potential, rock at top of a hill)
30
What is the 1st Law of thermodynamics
-the energy in the universe is constant
-energy is often transformed into heat
-energy can be transferred and transformed, but cannot be created or destroyed
31
What is the 2nd Law of thermodynamics
all energy transformations are inefficient- the amount of useful energy in the universe is decreasing and the amount of entropy (disorder) is increasing
32
What is entropy
measure of the energy not available for useful work in a thermodynamic process; disorganized, less order
33
What is free energy
𝝙G; energy available to do work in a chemical reaction
34
What is an exergonic reaction?
a release of energy; reactants contain more energy than products
35
What is an endergonic reaction?
requires an input of energy; products contain more energy than reactants
36
Hydrolysis is...
the conversion of ATP to ADP
37
what is ATP
two phosphate bonds that are unstable and release high energy during hydrolysis
38
What is phosphorylation
the transferring of a phosphate group to some other molecule, such as a reactant
39
3 keywords of Enzymes
1) activation site
2) reusable
3) catalyst
40
what is an Enzyme?
a biological catalyst (protein); can speed up chemical reactions in cells
41
enzymes reduce _____
activation energy
42
what are substrates
reactants
43
What is the structure of an enzyme?
-enzymes have a pocket called an active site
-reactants (substrates) bind to the active site
44
what is the active site
the region on the enzyme where the substrate binds
45
what is the induced fit
a substrates brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction
46
What is an inhibitor
a substance that interferes with an enzyme's activity
47
how many carbons are in one pyruvate molecule
3
48
what is fermentation
a catabolic process that makes a limited amount of ATP from glucose WITHOUT an electron transport chain... produces end product such as ethyl alcohol or lactic acid
49
what is aerobic respiration
a catabolic pathway for organic molecules using oxygen as the final electron acceptor in an electron transport chain, and ultimately producing ATP. Oxygen is consumed as a reactant along side the organic fuel
50
What is the main function of Cellular Respiration, and what are the 3 stages
mitochondria in animal, plant, and other organism's cells break down organic molecules, generating ATP and waste products (CO2, water, and heat). 3 stages: (1) Glycolysis (2) Pyruvate oxidation and citric acid cycle (3) oxidative phosphorylation
51
explain the process of Glycolysis
each glucose molecule is broken down into two molecules of pyruvate, the pyruvate then enters the mitochondrion. Glycolysis also produces NAD+ and 2 ATP. When O2 IS present, pyruvate goes on to be oxidized, when O2 IS NOT present, pyruvate continues on to the fermentation process.
52
Difference between the 2 photosystems
PS 1: has a chI a absorption peak at 700 nm (P700); PS 2: has a chI a absorption peak at 680 nm (P680)
53
label the regions indicated on the prokaryotic cell
(here's the labeled image)
54
what is the function of ribosomes and what are the two subunits.
complexes of rRNA and protein molecules that conduct protein synthesis. consist of a large and small subunit, free ribosomes and bound ribosomes
55
function of the plasma membrane
membrane enclosing the cytoplasm of every cell that acts as a selective barrier
56
function of the cell wall
rigid structure outside the plasma membrane
57
function of the nucleoid
region where the cell's DNA is located (not enclosed by a membrane)
58
function of the flagella
locomotion organelles of some prokaryotes
59
which two domains consist of prokaryotic cells
bacteria and archaea
60
In a eukaryotic cell, most of the DNA is stored in the ____, while in a prokaryotic cell DNA is stored in the _____
nucleus; nucleoid
61
as a cell increases in size, its surface area ___ . Cells have a ____ ratio of surface area to volume
greatly increases. Cells have a greater ratio of surface area to volume (because surface area increases at a much greater rate than volume, although they do both increase)
62
What is the nuclear envelope
encloses the nucleus, separating its contents from the cytoplasm; in a eukaryotic cell, the double membrane that surrounds the nucleus, perforated with pores that regulate traffic within the cytoplasm. The outer membrane is continuous with the ER. (2 layers)
63
what are the two components of chromatin
DNA and proteins
64
A sufficiently high ratio of surface area to volume is especially important in cells that __________________, such as __________
exchange a lot of material with their surroundings, such as intestinal cells
65
how do the microvilli of intestinal cells facilitate the exchange of material across the cell's plasma membrane?
they increase surface area without an appreciable increase in volume. They do this with their long, thin projections that move them across the membrane.
66
Define/differentiate free and bound ribosomes
FREE ribosomes are suspended in the cytosol and produce proteins that primarily function within the cytosol. BOUND ribosomes are attached to the outside of the endoplasmic reticulum or nuclear envelope and make proteins that are destined for insertion into membranes, for packaging within certain organelles (such as lysosomes), or for export from the cell (secretion).
67
what is the endomembrane system and what structures are included in it?
The endomembrane system includes the membrane-bound organelles of the eukaryotic cell, which includes: the plasma membrane, the nuclear envelope, the smooth and rough ER, the Golgi apparatus, lysosomes, vesicles, and vacuoles
68
label the crossed out terms on the ER and define them (only define the crossed out ones)
the smooth ER is the portion of the ER that is free of ribosomes. the rough ER is the portion of the ER with ribosomes. the ER lumen is the cavity/space that separates the internal compartment of the ER from the cytosol. transport vesicles are small membranous sacs in a eukaryotic cell's cytoplasm, carrying molecules produced by the cell.
69
what are the 3 major function of the smooth ER
The synthesis of lipids: enzymes synthesize lipids such as oils, steroids, and new membrane phospholipids. Detoxification of drugs and poisons: especially occurs in liver cells. Detoxification involves adding hydroxyl groups to drug molecules, making them more water-soluble and easier to flush from the body. The storage of calcium ions: for example, in muscle cells, the smooth ER membrane pumps calcium ions from the cytosol into the ER lumen.
70
What does the rough ER do with the secretory proteins: glycoproteins?
The ER membrane keeps them separate from proteins in the cytosol. They then depart from the ER wrapped in the membranes of vesicles.
71
What are the main functions of the ROUGH ER?
Creates secretory proteins (glycoproteins); acts as a membrane factory for the cells
72
label the crossed out parts of the Golgi apparatus
73
what is a lysosome? what does it contain? what is its pH range?
a membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists that many eukaryotic cells use to digest macromolecules. contains hydrolytic enzymes. has a near neutral pH
74
which human cells carry out phagocytosis?
macrophages, a type of white blood cells that helps defend the body by engulfing and destroying bacteria
75
describe food vacuoles
formed by phagocytosis; used as food by the cell
76
describe contractile vacuoles
helps to move excess water out of the cells of fresh water protists. this maintains a suitable concentration of ions and molecules inside the cell
77
describe central vacuoles in plants
in a mature plant cell, these vacuoles have diverse roles in growth, storage, and sequestration of toxic substances. play a major role in the growth of plant cells, which enlarge as the vacuole absorbs water, enabling the cell to become larger.
78
label the crossed out portions of the figure and explain how the elements of the endomembrane system function
the nuclear envelope is connected to the rough ER, which is continuous with the smooth ER. Membranes and proteins produced by the ER move via transport vesicles to the Golgi. the Golgi pinches off transport vesicles and others that give rise to lysosomes, other vesicles, and vacuoles. The lysosome is available for fusion with another vesicle for digestion. a transport vesicle carries proteins to the plasma membrane for secretion. The plasma membrane expands for fusion of vesicles; proteins are secreted from the cell via exocytosis.
79
what is the endosymbiont theory
the theory that mitochondria and plastids originated as prokaryotic cells engulfed by a host cell. The engulfed cell and its host cell then evolved into a single organism.
80
label the mitochondrion
81
label the chloroplast
82
what is the function of the mitochondria?
converts molecules absorbed into energy
83
what is the function of chloroplasts?
convert light absorbed by the cell into energy
84
what is the role of peroxisomes?
they are organelles containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide. This serves numerous different functions, one being that peroxisomes use oxygen to break fatty acids down into smaller molecules that are transported to mitochondria and used as fuel for cellular respiration.
85
what are the 3 main types of fibers that make up the cyto
skeleton?
Microtubules are the thickest, microfilaments are the thinnest, intermediate filaments are fibers with diameters in a middle range.
86
What are the three functions of the cytoskeleton?
maintenance of cell shape; cell motility (movement); anchorage of the nucleus and certain other organelles
87
what are the three functions of the cell wall
protects the plant cell, maintains its shape, and prevents excessive uptake of water.
