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Exam review Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

The steps of glycolysis

A

Reaction 1-3
Two molecules of ATP are used to phosphorylate substrate molecules
ATP comes from other reactions
Reaction 4
The six carbon compound, fructose 1,6-bisphosphate, is split into two different three carbon compounds: dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (G3P)
Reaction 5
DHAP is converted into a second G3P and each of the two G3P molecules proceeds through reactions 6 to 10
Reaction 6
An inorganic phosphate group is added to G3P, and an NAD+ molecule is reduced to form NADH
This reaction proceeds twice for the two G3P molecules produced
The reaction results in two 1,3-bisphosphoglycerate (BPG)
Reaction 7
ADP is converted to ATP by using substrate level phosphorylation
The products of the reaction are two 3-phosphoglycerate
Reaction 8 and 9
The three-carbon substrate molecules are rearranged and a water molecule is removed through condensation
This results in 2 phosphoenolpyruvate
Reaction 10
A molecule of ADP is converted to ATP by substrate level phosphorylation
This process occurs twice resulting in 2 ATP
The products of the reaction are two pyruvates

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2
Q

Calculating bond energy of a chemical reaction

A

energy in – energy out

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3
Q

Exergonic reactions

A

Exergonic - An exergonic reaction refers to a reaction where energy is released. Spontaneous

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4
Q

Endergonic reactions

A

Endergonic - An endergonic reaction is one that requires free energy to proceed. Not spontaneous

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5
Q

Steps of the krebs cycle

A

Reactions 1- 5
- Acetyl-CoA reacts with oxaloacetate to produce citrate
- Once citrate is formed, it breaks down to succinate.
- Two of these reactions are oxidation reactions that result in the release of two carbon dioxide molecules.
- Two reduction reactions, each of which reduces a molecule of NAD+ to produce a molecule of NADH

Reaction 6
- ATP is produced by substrate-level phosphorylation
- The phosphate group is then added to a molecule of guanosine triphosphate (GTP).
- The terminal phosphate group from GTP is then transferred to ADP to produce ATP.

Reactions 7-9
- These are oxidation reactions.
- NAD+ forms NADH
- Reduction of FAD to form FADH2
- These electron carriers are used to produce ATP in the oxidative phosphorylation pathway (Next system after krebs)
- The final product is oxaloacetate
- Oxaloacetate is regenerated, ready to react with more acetyl-CoA restarting the Krebs cycle

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6
Q

Steps of electron transport chain

A

Step 1:
- NADH (which is synthesised during the krebs cycle), becomes oxidised (gives up its proton (H+) and electron)
- becomes NAD+, its proton moves through complex 1.
- When this happens complex 1 becomes supercharged and is able to pump protons from the mitochondrial matrix into the intermembrane space.
- Now a proton gradient is beginning to form

Step 2:
- The electron moves to CoQ and waits
- Meanwhile FADH2 (Produced during Krebs cycle) approaches complex 2, it gives up its electron and becomes FAD into complex 2
- Complex 2 cannot become supercharge so the electron sits there before moving into CoQ (CoQ is the common electron acceptor for complex 1 & 2)

Step 3:
- The electrons are passed into complex 3 which becomes supercharged, moving the protons against the concentration gradient into the intermembrane space

Step 4:
- Complex 3 passes its electrons to cytochromeC which then passes them to complex 4

  • Comp4 becomes supercharged
  • Moves the protons against the gradient into the intermembrane space

Step 5:
- Comp4 passes the electron to the final electron acceptor, oxygen,
- O2 splits into two oxygen ions and protons are added, producing two water molecules

Chemiosmosis
Step 6:
- Now, ATP synthase is going to take advantage of the proton gradient in order to produce ATP. The protons want to flow down its gradient (flow from high concentration to low concentration to form an equilibrium) so protons move down ATP synthase, catalysing the reaction between ADP + Pi to form ATP
The protons that were moved through ATP synthase back into the mitochondrial matrix are now waiting for complexes 1, 3, and 4 to become supercharged again and allow the cycle to continue.

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7
Q

Chemiosmosis

A
  • Step 6 of ETC
  • ATP syntase is activated by a proton flowing down its system
  • The activation catalyses the reaction of ADP + Pi into ATP
  • The protons that were moved through ATP synthase back into the mitochondrial matrix are now waiting for complexes 1, 3, and 4 to become supercharged again and allow the cycle to continue
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8
Q

Steps of anerobic respiration

A
  • Follows the same steps as the electron transport chain but the final electron acceptor is something other than oxygen, (like a sulphur ion and will produce hydrogen sulphide instead of water)

Step 1: NADH+ Proton moves through complex 1, supercharging it

Step 2: FADH2 gives up an electron to complex 2, becomes FAD. Moves to CoQ with the first electron from complex 1

Step 3: Electrons move into complex 3, supercharging it

Step 4: Complex 3 passes its electrons to cytochromeC which then passes them to complex 4, comp 4 becomes supercharged

Step 5:
- Comp4 passes the electron to the final electron acceptor, sulphate
- Sulphate turns into hydrogen sulphide

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9
Q

Light dependent reaction steps

A

Step 1: Absoprtion of light
- Proton is absobed by P680 molecule in PS2, makes an excited electron that goes to an electron acceptor

  • Now P680 has a hole, so it splits a water molecule into H+ and O
  • P680+ accepts these electrons one at a time, and each is passed to another electron carrier.
  • P680+ then absorbs another photon, becomes reduced, and passes on another electron
  • This process occurs four times to form one oxygen molecule
  • The 4 H+ ions from the two water molecules remain in the thylakoid space.
  • The O atoms from 2 H20 form one O2 molecule and are released from the plant

Step 2: Transfer of electron
- From the electron acceptor, the energised electrons are transferred, one by one, to the electron transport system
- Small amounts of energy are released, its used by protein complex b6-f to pump hydrogen ion from the stroma, across the thylakoid membrane, and into the thylakoid space (creates gradient)

Step 3: Production of ATP
- Light energy is absorbed by photosystem I.
- This energy is transferred to the reaction centre P700, where electrons become excited
- Electrons are passed to a high-energy electron acceptor (Ferredoxin)

  • The lost electrons are replaced by those that have reached the end of the electron transport system from photosystem II

Step 4: Carbon fixation
- The electrons that were received by the electron acceptor from photosystem I are used by the enzyme NADP reductase to reduce NADP+ to form NADPH
- The power of NADPH will be used in the light-independent reactions

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10
Q

Steps of light independent reactions (calvin cycle)

A
  1. Carbon dioxide fixation
    - Carbon dioxide chemical bonds to a pre-existing molecule in the stroma called ribulose-1,5-bisphosphate (RuBP)
    - The resulting six-carbon compound is unstable and immediately breaks down into 2 identical three-carbon compounds called 3-phosphoglycerate (PGA)
  2. Reduction
    - The three-carbon compounds are in low-energy state. To convert them to a higher energy state, they are activated by ATP and then reduced by NADPH.
    - Result is two molecules of glyceraldehyde-3-phosphate (G3P)
    (In their reduced state, some of the G3P molecules leave the cycle and may be used to make glucose and other carbohydrates)
    - The remaining G3P molecules move onto the third phase
  3. Regenerating RuBP
    - Most of the reduced G3P molecules are used to make more RuBP.
    - ATP is required to break and reform the chemical bonds to make the five-carbon RuBP from G3P
    - The cycle must be completed six times to make one glucose molecule
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11
Q

Structure of chloroplast (its a pool)

A

Outer most lyer: Outer membrane (ground)
Middle layer: Intermembrane space (small, sort of empty space) (pool insulation of air)
Inner layer: Inner membrane (pool lining)

Stroma: Fluid in the chloroplast that things float in (water in a pool)
Thylakoid: Photosythesis site (Floaties in the pool)
Granum: Stacks of tylakoids (stacks of floaties)
Lumen: Protein filled space in thylakoids (air in floatie)

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12
Q

Hypertonic

A

The solution that has more dissolved particles (typically salt) than the amount of salt in the cell

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13
Q

Hypotonic

A

The cell has more particles (typically salt) than the solution its in

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14
Q

Isotonic

A

The amount of particles (typically salt) is the same in the solution as it is in the cell

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15
Q

Sensory neurons

A

Carry impulses from receptors in the eye (sight), ear (hearing), tongue (taste), and skin (pressure/heat) to the brain

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16
Q

Motor neurons

A

carry impulses from the brain to muscles (for movement) or a gland (for hormone secretion)

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17
Q

Interneurons

A

Connect neurons together

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18
Q

Endocrine system

A
  • Organ system that secretes most hormones
  • Major gland is pituitary gland
  • Pituitary works with hypothalmus
  • Helps regulate homeostasis because they help regulate and coordinate the functions of virtually all organ systems
  • Most hormones are produced in glands and released into the bloodstream
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19
Q

Central nervous system (CNS)

A

Brain and spinal chord

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20
Q

Peripheral nervous system (PNS)

A

All other nerves in the body

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21
Q

Nervous system and homeostasis

A
  • The control system that enables animals to detect a stimulus and coordinate a response.
  • A stimulus is when a change in the environment is detected and your body responds to it
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22
Q

Five functions of endocrine system

A
  • Regulate metabolism
  • Maintain water, salt, and nutrient balance in blood
  • Control responses to stress
  • Regulate growth, development, and reproduction
  • Produce hormones
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23
Q

Dendrites

A
  • Branching terminals
  • Receive nerve impulses from other neurons or sensory receptors
  • Relay the impulse to the cell body
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24
Q

Axon

A
  • Conducts impulses away from the cell body
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25
Q

Myelin sheath

A
  • Protects neurons
  • Speeds rate of neuron transmission
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26
Q

Reflex arc

A
  1. Receptor recieves an initial stimulus
  2. Sensory nerve carries impulse to the spinal column or brain
  3. Intermediate nerve fibre interprets signal and issues appropriate response
  4. Motor carries response from spinal chord to the muscle or organ
  5. Effector organ carries out response
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27
Q

Dopamine

A

Function:
- Pleasure

Effects:
- Too much can lead to schizo
- Too little can lead to parkinsons

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28
Q

Serotonin

A

Fuction:
- Mood control

Effects:
- Too little can lead to depression

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29
Q

Endorphins

A

Fuction:
- Brain synapse painkiller
- Affects emotional areas of brain

Effects:
- Too little can lead to alcoholism

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30
Q

Norepinephrine

A

Fuction:
- Used by brain and autonomic neurons
- Prepares body for fight or flight

Effects:
- Too much can lead to high blood pressure, anxiety, insomnia
- Too little can lead to hunger and exhaustion

31
Q

Population change equation

A

Δ N = (B + I ) – (D + E)

Δ N = population change
B= birth
I= immigration
D= death
E= emigration

32
Q

Population growth equation

A

gr = ΔN/Δt

gr= growth rate

ΔN = change in population size

Δt = change in time

33
Q

Per captita growth rate

A

cgr = Δ N/N

cgr = per capita growth

Δ N= change in the number of individuals

N= original number of individuals

34
Q

Quadrat equation

A

Dp = N / A
N = sum of individuals in the quadrats
A = total area of the quadrats

35
Q

Mark recapture equation

A

Population size (N) = (number original marked x total individuals in recapture) / marked individuals in recapture

36
Q

Type 1 survivorship

A

Exponential decay

37
Q

Type 2 survivorship

A

Linear

38
Q

Type 3 survivorship

A

Reversed exponential growth

39
Q

r-species

A
  • Have a short life span
  • Become sexually mature at a young age
  • Produce large broods of offspring
  • Provide little or no parental care to their offspring
40
Q

k-species

A
  • Have a relatively long life span
  • Become sexually mature later in life
  • Produce few offspring per reproduction cycle
  • Provide a high level of reproductive care
  • Live at their environments carrying capacity
41
Q

Interspecific competition

A
  • A situations in which two or more populations compete for limited resources
  • Often one species will out-compete the other
42
Q

Instraspecific competiton

A
  • Members of the same population complete for resources.
43
Q

Transcription - DNA to mRNA

A

Initiation:
- RNA polymerase binds to a region of a gene called the promoter. This
- Signals the DNA to unwind so the enzyme can ‘‘read’’ the bases in one of the DNA strands
- The enzyme is now ready to make a strand of mRNA with a complementary sequence of bases

Elongation:
- RNA polymerase reads the unwound DNA strand and builds the mRNA molecule, using complementary base pairs
- Adenine (A) in the DNA binds to a uracil (U) in the RNA

Termination:
- RNA polymerase crosses a stop (termination) sequence in the gene
- The mRNA strand is complete, and it detaches from DNA.

44
Q

Translation - mRNA to protein

A

Initiation:
- The initiator tRNA binds to the codon UAC anticodon.
- Collectively, the codons of mRNA that are read to produce an amino acid sequence; it is set by the start codon (AUG)

Elongation:
- According to the codons found in the mRNA, the polypeptide chain keeps growing.
- Each amino acid has a peptide bond attaching it to the growing chain.
- Elongation continues till the whole gene is translated.

Termination:
- When the ribosome reaches a stop codon, such as UAA, UAG, or UGA, translation is finished since these codons lack tRNAs.
- When this happens, the translation stops, and the newly produced polypeptide chain is released.

45
Q

Types of chromosome mutations (changes in the chromosome and involve many genes)

A

Deletion:
Loss of one or more nucleotides from a segment of DNA
A deletion can involve the loss of any number of nucleotides, from a single nucleotide to an entire piece of a chromosome
Duplication:
One or more copies of a DNA segment (which can be as small as a few bases or as large as a major chromosomal region) is produced

Inversion:
A chromosome breaks and when put back together one half is placed backwards

Translocation:
Occurs when a piece of one chromosome breaks off and attaches to another chromosome
This type of rearrangement is described as balanced if no genetic material is gained or lost in the cell - If there is a gain or loss of genetic material, the translocation is described as unbalanced

46
Q

Lac operon

A
  • This encodes proteins that are able to break down lactose to use as energy
  • Inducible operon - Usually inactive until lactose is present, then an activator will turn it on
  • In the absence of lactose, the lac repressor proteins binds to the operator and prevents RNA polymerase from binding to the promoter, and transcription cannot occur
  • In the presence of lactose, a derivative called allolactose is produced, which binds to the repressor and the repressor can no longer bind to the operator. This results in the transcription of the genes to produce the required enzymes
47
Q

Types of single gene mutations (Changes in the nucleotide sequence of a gene)

A

Point mutations:
- Mutations involving a single base pair
- Can result in a frameshift mutation, silent mutation, missense mutation, or nonsense mutation

Frameshift mutations:
- Deletes of inserts an extra nucleotide
- Causes the entire reading frame to be altered ( ATA CCG CAG to GAT ACC GCA G or TAC CGC AG)

Silent mutations:
- Has no effect on the amino acid sequence
- May occur when one nucleotide is substituted for another but the error will still code for the same amino acid

Missense mutations:
- Change in amino acid sequence
- Occurs when one base is substituted for another that does result in a new amino acid

Nonsense mutations:
- Occurs when a gene’s coding sequence is changed in such a way that it results in a premature stop
- A shorted protein or no protein at all will be made

48
Q

Comparing C3, C4 and CAM plants

A

C3 plants:
- produces a three-carbon compound via the Calvin cycle

C4 plants:
- makes an intermediate four-carbon compound that splits into a three-carbon compound for the Calvin cycle

CAM plants:
- gather sunlight during the day and fix carbon dioxide molecules at night

49
Q

Characteristics of polar molecules

A
  • Has regions of positive and negative charge
  • Asymetrical
  • Hydrophile
50
Q

Characteristics of covalent molecules

A
  • Hydrophobe
  • Low boiling/melting points
  • Cant conduct electricity ( do not have charged particles capable of transporting electrons)
51
Q

Structure of mRNA

A
  • mRNA is a long, single-stranded molecule consisting of nucleotides attached by phosphodiester bonds
  • It contains four nitrogenous bases, adenine, guanine, cytosine and uracil.
52
Q

Structure of tRNA

A
  • Has a distinctive folded structure with three hairpin loops that form the shape of a three-leafed clover
  • One of these hairpin loops contains a sequence called the anticodon, which can recognize and decode an mRNA codon
  • Each tRNA has its corresponding amino acid attached to its end
53
Q

anabolic reactions

A
  • The building of larger, complex molecules from smaller, simpler ones
  • Require an input of energy
54
Q

Catabolic reactions

A
  • Breakdown of large, organic molecules into smaller, simpler ones
  • Accompanied by a release of energy
55
Q

Exergonic reaction

A
  • Chemical reaction where the change in the free energy is negative (there is a net release of free energy)
  • Spontaneous

Change in free energy = energy of product - energy of reactants

(Energy out - energy in)

56
Q

Endergonic reactions

A
  • A reaction that requires energy to be driven
  • The change in the free energy is negative

Change in free energy = energy of product - energy of reactants

(Energy out - energy in)

57
Q

Decomposition reaction

A

AB = A + B

58
Q

Single displacement reaction

A

AB + C = AC + B

59
Q

Double displacement reaction

A

AB + CD = AD + CB

60
Q

Synthesis reaction

A

A + B = AB

61
Q

Structure of nucleotides

A

. O . O .
HO- P - O N . NH
OH I N N NH2
I. O .I
. .
OH OH
Sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base

62
Q

Modifications of pre-mRNA

A
  • Addition of a 5’ cap
  • Addition of a 3’ poly-A tail
  • Removal of introns (non-coding regions, interspersed among exons)
63
Q

Dispersal patterns

A

Clumped Distribution:
- Organisms clump around resources,
- Common among species in which individuals gather into groups for positive interactions

Uniform distribution:
- Resources are evenly distributed but scarce, population exhibits uniform distribution

Random distribution:
- Resources are plentiful and uniformly distributed across an area
- There is no need for individuals to defend their share and interactions between individuals are neutral

64
Q

Interactions between species

A

Parasitism:
- a symbiotic relationship in which a symbiont lives off and harms the host
(tapeworms)

Mutualism:
- A type of symbiotic relationship in which both species benefit from the relationship
(teeth cleaning birds)

Commensalism:
- A symbiotic relationship in which one partner benefits and the other partner neither benefits nor is harmed

65
Q

Enzymes in DNA replication

A

DNA polymerase 3 - Enzyme that catalyses the addition of new nucleotides, it attaches to the 3 end of the preexisting chain of nucleotides and travels from 5 to 3` direction, “The builder” - Appears only in DNA replication
Enzyme helicase - Cleaves hydrogen bonds that link bases together, “Unzips the DNA”
Single strand binding protein - Help stabilise the unwound single strands so that they dont reform into a double helix
Enzyme Topoisomerase 1 - Helps relieve stress and regulate/stop supercoiling
Enzyme Topoisomerase 2 - Helps to relieve the strain on the double helix ahead of the replication fork
Primase - Polymerase can’t figure out where to start without a primer. Primase makes it so that DNA polymerase can figure out where to start to work, “The initializer”, the primer is actually made of RNA
Ligase - Helps glue the DNA fragments together, “The gluer”

66
Q

Structure of cell membrane

A
  • Phospholipid bilayer
  • Contain proteins to allow things through the membrane
67
Q

Function of catalysts

A

increase the reaction rate

68
Q

Calculating type of bond from electronegativity

A

Ionic:
- More than 1.7

Polar covalent:
- between 0.4 and 1.7

nonpolar covalent:
- under 0.4

69
Q

Negative and positive feedback loops

A

Positive feedback loops
- enhance or amplify changes
- moves a system away from its equilibrium state and make it more unstable

Negative feedbacks
- dampen or buffer changes; this tends to hold a system to some equilibrium state making it more stable.

70
Q

Parts of feedback systems

A
  • stimulus
  • sensor
  • control center
  • effector
71
Q

Blood sugar and how it is regulated by homeostasis

A

When a person’s blood sugar is too high, their pancreas secretes more insulin. When their blood sugar levels drop, their pancreas releases glucagon to raise them

With diabetes the pancreas cant produce enough or any insulin or the body is resistant to insulin

72
Q

Hershey and Chase

A
  • 1952: Alfred Hershey and Martha Chase designed an experiment to rule out protein in favour of DNA as the hereditary material.
  • They used bacteriophages, which are viruses that infect bacteria
  • They aimed to determine which part of the virus- the DNA in the viral core or the protein in the capsid- enters bacterial cells and directs the production of more viruses
  • They used radioactive isotopes to trace each type of molecule (DNA or protein)

Experiment #1: A virus with radioactive DNA was allowed to infect E coli bacteria. The cells were then agitated and were then centrifuged to separate the infected bacterial cells, which formed a pellet at the bottom of the centrifuge tube, and the liquid medium, which contained the remnant bacteriophage “ghosts”.
- Result: most of the radioactively labelled DNA was in the bacteria and not in the liquid. This could only happen if the viral DNA entered the bacteria

Experiment #2: A virus with a radioactively labelled protein was allowed to infect the E coli bacteria.
Same procedure was followed as the first experiment.
Result: most of the radioactively labelled protein was the in liquid medium and not in the bacteria. This shows that the radioactive protein in the viral capsid remained as part of the bacteriophage ghosts and had not been injected into the bacteria.

73
Q

Sodium potassium pump

A

The Na+K+-ATPase pump helps to maintain osmotic equilibrium
- 3 sodium ions bind to the pump.
- A phosphate from ATP is donated to the pump (energy used)
- Pump changes shape and releases sodium ions outside of the cell.
- 2 potassium ions bind to the pump and are transferred into the cell.
- Phosphate group is released and pump returns to its original shap

Grade 12 biology (6 decks)

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