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Question 1

Image of monomer

Answer 1

phosphate head, ribose/deoxyribose sugar, nitrogen base

Question 2

tRNA vs DNA

Answer 2

tRNA - Uracil, ribose, more 02
DNA - thymine, deoxyribose, less 02

Question 3

Why template strand copied

Answer 3

Has promoter region

Question 4

Respiration

Answer 4

Glucose + oxygen –> carbon dioxide water
Glycolysis (cytosol)
Input = Glucose, NAD+, ADP + Pi
Output = Pyruvate, NADH, ATP
2 ATP

Crebs (Matrix of mitochondria)
Input = 2 acetyl CoA VIA 2 Pyruvate, NAD+, FAD, ADP + Pi
output = Co2, NADH, FADH, ATP
2 ATP

ETC (Cristae)
Input = O2, NADH, FADH2, ADP + Pi
Output = H2O, NAD+, FAD, ATP
32-34 ATP

Question 5

Photosynthesis

Answer 5

Carbon dioxide + water –> glucose + oxygen + water
Light dependent (grana in the thylakoid membranes)
Input = NADP+, ADP + Pi, H2O
Output = NADPH, ATP, O2

Light independent (stroma)
Input = NADPH, ATP, CO2
Output = NADP+, ADP + Pi, Glucose

Question 6

Antibiotic resistance

Answer 6

Bacteria species use a plasmid that has the antibiotic resistant gene and this will confirm if the vector cell has the recombinant plasmid (if survive the bacteria)

Question 7

Out of Africa

Answer 7

1. First wave out of Africa was Homo Erectus (some stayed)
2. The ones that stayed evolved into Homo heidelbergensis → In Asia and Europe, Homo heidelbergensis gave rise to Homo neanderthals and Homo denisovans
3. Homo heidelbergensis that stayed in Africa evolved into Homo sapiens about 300 000 years ago
4. Homo Sapiens left Africa and everything else became extinct

Question 8

Positive control

Answer 8

Basis of comparison but have a known predicted change

Question 9

Negative control

Answer 9

Blank setup, nothing should happen, acts as point of comparison

Question 10

Vector

Answer 10

Way of delivering gene of interest into bacteria cell

Question 11

Older dating use vs younger dating

Answer 11

Potassium to argon (older)
Carbon 14 to nitrogen (young)

Question 12

PAM

Answer 12

A specific sequences of nucleotides that binds to the gene of interest guides Cas9 to identify the gene location

Question 13

Cas9

Answer 13

cleaves DNA at specific base sequences.

Question 14

gRNA

Answer 14

RNA sequence complementary to gene of interest that provides the platform for the Cas9 protein to bind to synthesis DNA

Question 15

CRISPR natures way

Answer 15

1. Bacteriophage virus lands on a cell and injects its DNA
2. Viral genome gets incorporated into CRISPR region
3. When viral DNA is transcribed to mRNA, it becomes guide RNA and forms a complex with Cas 9 enzyme which float around in the cell with the RNA
4. When the same virus reinjects its DNA into the cell, Cas 9 have complementary RNA and will cut up viral DNA

Question 16

CRISPR application

Answer 16

1. Scientists manufacture cas9 protein, guide RNA and PAM- specific to the target DNA
2. The cas9 will identify the PAM sequence and guide RNA directs it to cut both strands of DNA
3. Scientists can insert a new piece of DNA (donor DNA) at the site of the cut. They may also remove or replace sections of DNA or add and delete nucleotides
4. The cell detects and repairs the broken strand of DNA. When the DNA is repaired any changes made are integrated into the genomic DNA.

Question 17

Homologous structures

Answer 17

Structures that have been derived from a common ancestor and thus show similarities in structure, but have different functions.
Example: The bones of a bat’s wing are homologous to those of a whale’s flipper, even though one structure is specialised for flying and the other for swimming.

Question 18

Vestigial structures

Answer 18

Structures that are non-functional remnants of structures that were functional in ancestral species.
Example: Whales are mammals evolved from a terrestrial mammalian ancestor, but are now specialised for life in the seas. Their skeletons show the presence of a reduced pelvis and, in some cases, vestiges of the bones of the hind limbs.

Question 19

Analogous structure

Answer 19

a feature found in two unrelated species, having evolved independently in each due to similar selection pressures

Question 20

Secondary protein structures

Answer 20

Alpha helix: single twisted strand. Help increase SA:V, can stretch / relax and contract - muscle fibres.
Beta-pleated sheets: staggered fold. Can stretch, give flexibility to the protein, maintains a structure / appearance surrounding
Random coiling: often the active site of an enzyme allowing a substrate to successfully bind

Question 21

C3, C4, CAM

Answer 21

C3 - Cool temp, moist conditions, Rubisco, Location of LID in, mesophyll cells, Open stomata, Carbon fixation during day
C4 - Hot arid environment, exposed to drought, PEP carboxylase (Rubisco starts LID), Location of LID in bundle sheath cells
don’t open stomata, Carbon fixation during day
CAM - warm temp, tropic regions, PEP carboxylase (Rubisco starts LID), Location of LID in mesophyll cell, open stomata at night only, Carbon fixation at night

Question 22

Sympatric speciation

Answer 22

1. A single population is divided by prezygotic isolation barriers. Initially there is some gene flow between populations
2. Over many generations, genetic divergence occurs. The two palm trees produce flowers at different times of the year; therefore, there is no reproduction occurring between the two species. Eventually the isolated populations respond differently to environmental selection pressures, which leads to different phenotypes being selected for by natural selection or genetic drift.
3. When they can no longer reproduce fertile offspring when brought together they become two different species.

Question 23

mutations in chromosome

Answer 23

Deletions - When a chromosome breaks in two places, losing the middle section, and the remaining sections rejoin.
Inversion - When a chromosome breaks in two places, and middle piece turns around and joins up again - normal
Translocation - When a piece of a chromosome breaks off and joins up with another chromosome
Duplication - When a section of chromosome replicates (set of genes repeated, can be thousands repeats)

Question 24

Phospholipid bilayer

Answer 24

Hydrophobic
Head - hydrophilic
Tail - hydrophobic

Question 25

Respiration

Answer 25

Glucose + oxygen –> carbon dioxide water

Question 26

Photosynthesis

Answer 26

Carbon dioxide + water –> glucose + oxygen + water

Question 27

what does CRISPR do bacteria

Answer 27

recognise foreign viral DNA sequence strand in spacer region upstream of PAM

Question 28

Repressor gene

Answer 28

Produces proteins that controls other genes

Question 29

Absolute dating

Answer 29

Absolute dating involves identifying the age of rock or fossils using radiometric dating techniques.

Question 30

Cas9 bacteria

Answer 30

Binds to PAM and upstream of PAM and unravels DNA
gRNA checks for complementarity and then Cas9 cleaves creating blunt ends

Question 31

PCR

Answer 31

1. Denaturing - double stranded piece of DNA is heated to approx 94°C, causing the hydrogen bonds between the complementary strands to break.
2. Annealing- temp is lowered to approximately 55 °C for two minutes. Primers are added and anneal to the complementary regions of the DNA strand. Primers bind to the target DNA sequences at 3′ ends and initiate DNA synthesis (polymerisation).
3. Extension - temp is raised to approx 72°C and taq polymerase synthesises a new strand of DNA (using the primers as a starting point) by adding free nucleotides.
   This process is repeated, doubling the DNA each time.