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Biology exam gr 12 > biology exam gr 12 > Flashcards

biology exam gr 12 Flashcards

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1
Q

What is an integral protein?

A

Embedded in the lipid bilayer and has one region that interacts with the hydrophobic core.

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2
Q

What role does cholesterol play in cell membranes?

A

Regulates membrane fluidity.

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3
Q

Define glycoprotein.

A

Proteins with attached carbohydrate chains that serve crucial roles in cell recognition, cell signaling, and cell adhesion.

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4
Q

What is a glycolipid?

A

Lipids with an attached carbohydrate chain that play a crucial role in cell recognition and membrane stability.

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5
Q

What is the phospholipid bilayer?

A

A fluid barrier that separates the cell’s interior from its external environment.

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6
Q

What is a hypotonic solution?

A

A solution that has a lower concentration of solutes compared to another solution, causing water to flow into the cell.

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7
Q

What is a hypertonic solution?

A

A solution with a higher concentration of solutes compared to another solution, causing water to flow out of the cell.

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8
Q

What is an isotonic solution?

A

A solution with the same concentration of solutes as another solution, causing no net movement of water.

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9
Q

What does lyse mean?

A

The breakdown or destruction of a cell, usually by disrupting its outer membrane.

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10
Q

How do enzymes work?

A

They speed up chemical reactions by lowering the activation energy (Ea).

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11
Q

What are the four levels of enzyme structure?

A
  • Primary
  • Secondary
  • Tertiary
  • Quaternary
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12
Q

What is non-competitive inhibition?

A

A way to inactivate an enzyme that does NOT involve competing with the substrate.

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13
Q

What is competitive inhibition?

A

The inhibitor binds to the enzyme’s active site, preventing substrate from binding.

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14
Q

What is feedback inhibition?

A

A process where the end product of a pathway inhibits an earlier step, preventing overproduction.

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15
Q

Define substrate.

A

A substance that an enzyme binds to in order to cause a reaction to occur.

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16
Q

What is the active site of an enzyme?

A

The location on an enzyme where substrates can bind.

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17
Q

What is the induced-fit model?

A

A model where a substrate binds to an active site, and both change slightly, creating an ideal fit for catalysis.

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18
Q

What are allosteric inhibitors?

A

Molecules that regulate enzyme activity by binding to a site on the enzyme other than the active site.

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19
Q

What is activation energy (Ea)?

A

The minimum amount of energy needed to start a chemical reaction.

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20
Q

What is glycolysis?

A

A process requiring an investment phase of 2 ATP to start, producing 4 ATP, 2 NADH, and 2 pyruvates.

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21
Q

What occurs during pyruvate oxidation?

A

Oxidizes 2 pyruvates into 2 acetyl-CoA and produces 2 NADH.

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22
Q

What is the Kreb’s cycle?

A

Uses 2 Acetyl-CoA to produce 1 ATP, 3 NADH, and 1 FADH, repeating to produce a total of 2 ATP, 6 NADH, and 2 FADH.

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23
Q

What happens in the electron transport chain?

A

The first protein complex starts with higher energy, oxidizing NADH and FADH2, losing energy as it passes through each complex.

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24
Q

What is chemiosmosis?

A

The movement of H+ across the membrane down to a low concentration (proton gradient) to produce ATP.

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25
What is the structure of a mitochondrion?
Same as mitochondria, just means a singular term.
26
What is substrate-level phosphorylation?
A high-energy substrate molecule donating a phosphate group to ADP, creating ATP.
27
What are NAD and NADH?
NAD+ is the oxidized form, and NADH is the reduced form, storing energy and helping produce ATP.
28
What is ATP?
The main energy currency of cells, composed of an adenosine molecule and three phosphate groups.
29
What is FAD?
An electron carrier that becomes reduced to FADH2 during the Krebs cycle.
30
What is the intermembrane space?
The area between the inner and outer mitochondrial membranes.
31
Define electrochemical gradient.
A difference in ion concentration and electric charge across a membrane used to make ATP.
32
What is oxidative phosphorylation?
The process that produces the majority of ATP via the electron transport chain.
33
What is chlorophyll?
A pigment found within chloroplasts that absorbs light energy.
34
What are chloroplasts?
Organelles where photosynthesis occurs, containing thylakoids and stroma.
35
What is Photosystem I?
A photosystem that inputs light energy and outputs NADPH.
36
What is Photosystem II?
A photosystem that inputs light energy and water, outputting oxygen, hydrogen ions, and energized electrons.
37
What are light-dependent reactions?
Reactions occurring in thylakoid membranes where light energy is absorbed to produce ATP and NADH.
38
What are light-independent reactions?
Reactions occurring in the stroma that use ATP and NADPH to create glucose.
39
What is carbon fixation?
The process where plants take CO2 from the air and turn it into glucose during photosynthesis.
40
What factors affect photosynthetic rate?
* Light intensity * Temperature * Oxygen (O2)
41
What are dark reactions?
The second stage of photosynthesis where ATP, NADPH, and CO2 are used to make glucose.
42
What is excitation in the context of photosynthesis?
When light energy makes electrons in chlorophyll gain energy and jump to a higher energy level.
43
What did Watson & Crick discover?
The DNA molecule exists in the form of a 3-D double helix held together by hydrogen bonds.
44
What was the focus of the Hershey & Chase experiment?
To determine whether DNA or protein was the genetic material of a virus.
45
What is the structure of DNA?
A double helix that carries genetic information.
46
What does antiparallel mean in DNA?
The opposite orientation of the two strands in a DNA double helix.
47
Define complementary base pairing.
The specific pairing of nitrogenous bases in DNA and RNA.
48
What are purines?
A type of nitrogenous base that is a crucial building block of DNA and RNA.
49
What are pyrimidines?
A group of nitrogenous bases that are essential building blocks of DNA and RNA.
50
How does RNA compare to DNA?
RNA is single-stranded, contains ribose, and has uracil instead of thymine.
51
What do 5’ and 3' refer to in nucleic acids?
The orientation of a DNA or RNA strand, indicating the number of carbon atoms in the sugar-phosphate backbone.
52
What is DNA replication?
The process where a cell duplicates its DNA, creating two identical DNA molecules.
53
What is the function of DNA helicase?
Enzymes that unwind the two strands of DNA by breaking hydrogen bonds.
54
What is the role of topoisomerase?
Relieves tension in DNA strands by cutting one or two strands near the replication fork.
55
What is a replication bubble?
The space between two replication forks filled with newly replicated DNA.
56
What is a replication fork?
The Y-shaped structure formed when the two strands of DNA are separating.
57
What does DNA polymerase I do?
Removes primer and replaces it with base pairs, starting proofreading.
58
What is the function of DNA polymerase III?
Builds new strands by adding complementary base pairs in the 5’ to 3’ direction.
59
What are Okazaki fragments?
Short, newly synthesized DNA fragments formed on the lagging strand during DNA replication.
60
What is the leading strand?
The new strand of DNA synthesized continuously in the 5' to 3' direction.
61
What is the lagging strand?
Created 5' to 3' and grows away from the replication fork.
62
What is an RNA primer?
Base pair start code for polymerase III.
63
What does RNA primase do?
Sets down RNA priming to create a docking site for polymerase.
64
What is the role of DNA ligase?
Catalyzes the reaction of joining two large molecules by creating a new chemical bond.
65
What is mRNA?
Carries genetic info copied from DNA in the nucleus to the ribosomes.
66
What is the function of tRNA?
Transports amino acids to the ribosome during translation.
67
Define codon.
A sequence of three RNA bases on mRNA that codes for one specific amino acid.
68
What is an anticodon?
A sequence of 3 nitrogenous bases on a tRNA molecule that is complementary to a codon on mRNA.
69
What is the A site in ribosomes?
The entry point for a new tRNA carrying an amino acid.
70
What is the P site in ribosomes?
Holds the tRNA with the growing polypeptide chain.
71
What is a reading frame?
The way mRNA is read by the ribosome in sets of three bases at a time during translation.
72
What is a silent mutation?
Changes a base but still codes for the same amino acid.
73
What is a missense mutation?
Changes a base and results in a different amino acid.
74
What is a nonsense mutation?
Changes a base to a stop codon, causing early termination of the protein.
75
What is a frameshift mutation?
One or more bases are inserted or deleted, changing the codon.
76
What is substitution in DNA?
One base is replaced, which may change one or none amino acids.
77
What is deletion in DNA?
Base(s) removed, potentially causing a big effect.
78
What is insertion in DNA?
Base(s) added, potentially causing a big effect.
79
What are restriction enzymes?
Special proteins that cut DNA at specific sequences.
80
What is a recognition site?
A specific sequence of DNA bases that a restriction enzyme recognizes and cuts.
81
What are blunt ends in DNA?
Made by straight cuts through both DNA strands, leaving no overhangs.
82
What are sticky ends in DNA?
Made by staggered cuts, leaving short, single-stranded overhangs.
83
What is agarose gel?
A jelly-like substance used in gel electrophoresis to separate DNA fragments by size.
84
What is recombinant DNA?
DNA that has been artificially combined from two or more different sources.
85
What is DNA cloning?
The process of making exact copies of a specific DNA fragment.
86
What is the purpose of biotechnologies?
To use living organisms to solve problems and create useful products.
87
What are plasmids?
Small, circular pieces of DNA found in bacteria that replicate independently.
88
What is homeostasis?
The body's way of keeping internal conditions stable despite changes in the environment.
89
What is a positive feedback loop?
A change that completes a process, such as childbirth or blood clotting.
90
What is a negative feedback loop?
Reverses changes to keep the body stable.
91
How does the body control water balance?
Using the hormone ADH to adjust how much water the kidneys reabsorb.
92
What is an osmotic gradient?
The kidney helps draw water out of the nephron for reabsorption.
93
What are the roles of the kidney?
* Filter blood * Remove wastes * Balance water, ions, and pH * Control blood pressure * Produce key hormones
94
What is diabetes?
A condition where the body can't properly control blood sugar.
95
What is a myelinated nerve impulse?
Travels quickly by jumping between gaps in the myelin sheath.
96
What are neurons?
Specialized cells that transmit electrical signals through the body.
97
What are the main components of a neuron?
* Dendrites * Cell body * Axon * Axon terminals

Biology exam gr 12 (2 decks)

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