You Got This 💜 Flashcards
1
Q
Allergic Response
A
- Upon initial exposure to the allergen, complementary B cells are activated and plasma B cells will release IgE.
- IgE binds to mast cells to sensitise them.
- Upon re-exposure to the allergen, the allergen will bind and cross link to the IgE on sensitised mast cells. Triggers release of large amounts of histamine and causes symptoms of inflammation.
2
Q
Inflammation
A
- Inflammation is initiated when damaged cells release cytokines to trigger nearby mast cells to release histamine.
- Histamine binds to blood vessels, resulting in vasodilation that increases blood flow (redness). Increased permeability makes the blood vessel and migrate to the blood vessels more leaky (swelling).
- Leukocytes can easily leave the blood vessels to the area of inflammation.
3
Q
Cell-mediated Response
A
- Antigen presenting cells carrying a target antigen on their MHC II binds to a complementary naive T cell’s T cell receptor, triggering release of cytokines.
- The naive T cell is activated and undergoes clonal expansion and differentiation into helper T and Cytotoxic T cells.
- T helper cells will regulate the action of other immune cells whilst cytotoxic T cells will travel to the area of infection, bind to affected cells displaying the target antigen and will trigger the death of target cells via apoptosis or perforin or granzymes.
4
Q
Attenuation (Trp High)
A
- Transcription + translation of the trp operon begin and occur simultaneously.
- When RNA polymerase reaches the attenuator in leader sequence it codes for 2 trp and causes terminator hairpin like structure in mRNA.
- This hairpin like structure causes pre-mature termination of transcription.
- RNA polymerase and mRNA detach from DNA and ribosome gets separated from mRNA.
- Non-functional protein is made.
5
Q
Repression (Trp High)
A
- High amount of trp in cell
- Trp attaches to repressor protein to activate it.
- Activated repressor protein binds to operator region and prevents RNA polymerase from transcribing structural genes.
6
Q
Antigen Presentation
A
- APCs present the antigen on MHCII marker to T helper cells.
- T helper cell receptor binds with antigen and become activated.
7
Q
Humoral Response
A
ANTIGEN PRESENTATION (2 MARKS)
- APCs present the antigen on MHCII marker to T helper cells.
- T helper cell receptor binds with antigen and become activated.
HUMORAL (3 MARKS)
- T helper cells release cytokines to activate naive B cells which undergo clonal expansion and differentiation into plasma B cells and memory B cells.
- Plasma B cells release antibodies into the bloodstream to destroy the pathogen.
- Memory cells circulate in blood, to trigger strong + quick immune response upon reexposure to pathogen.
8
Q
Bioethanol Production
A
- Biomass is made up of cellulose, broken down by heating, grinding and mashing.
- Broken down biomass is then exposed to enzymes which break down the cellulose and convert them into glucose and other sugars. This breaking down is aided by water (hydrolysis)
- Yeast is used to facilitate anaerobic fermentation of the sugars produced in step 2, ethanol and Co2 is produced.
- Ethanol is distilled via removal of water, making bioethanol. Bio ethanol is then purified and ready to be used as liquid fuel.
9
Q
Light Dependent (Grana/Thylakoid Membrane)
A
Inputs:
- Light
- H20
- NADP+
- ADP +Pi
Outputs:
- NADPH
- O2
- ATP
10
Q
Light Independent (Stroma)
A
Inputs:
- NADPH
- CO2
- ATP
Outputs:
- NADP+
- Glucose
- ADP +Pi
11
Q
C4 Plants
A
Carbon Fixation(mesophyll)
- PEP carboxylase + CO2 = malate
Calvin Cycle (bundle sheath)
- Malate broken down into
pyruvate and CO2
- Pyruvate recycled back into PEP to
fix carbon again
- CO2 binds to Rubisco to produce
Glucose
E.g: Sorghum, sugarcane, maize
12
Q
Aerobic Respiration
A
- Glycolysis (Cytosol):
Inputs:- Glucose
- NAD+
- ADP+Pi
Outputs:
- Pyruvate
- NADH
- 2 ATP
- Krebs Cycle (Matrix of mitochondria)
Inputs:- Pyruvate
- FAD+
- NAD+
- ADP+Pi
Outputs:
- CO2
- FADH2
- NADH
- 2 ATP
- Electron Transport Chain (Cristae of mitochondria)
Inputs:- O2
- FADH2
- NADH
- ADP+Pi
Outputs:
- H2O
- NAD+
- FAD+
- 26 or 28 ATP
13
Q
Anaerobic Fermentation (Humans)
A
- Glycolysis (cytosol):
Inputs:
- Glucose
- NAD+
- ADP +PiOutputs:
- Pyruvate
- 2 ATP - Lactic Acid Fermentation (cytosol)
Inputs:
- Pyruvate
- NADHOutputs:
- Lactic Acid
- NAD+
14
Q
Fossilisation (Example)
A
- Dinosaur dies in a river
- The body is covered with sediment. The soft tissues decompose and the hard body structures become fossilised by permineralisation.
- The sedimentary layers accumulate and the resultant pressure forms sedimentary rock.
- The earth’s movements raise the layers of the rocks to the surface.
- The rock erodes, exposing the fossilised body structures.
15
Q
Natural Selection
A
- Variation: Individuals in a population vary genetically, which leads to phenotypic differences.
- Selection Pressure: An environmental selection pressure impacts the survivability of organisms within a population and their ability to reproduce.
- Selective Advantage: Individuals with phenotypes that are more advantageous against selection pressure confer a selective advantage, allowing them to survive and reproduce more successfully.
- Heritability: The advantageous trait must be heritable, allowing it to be passed on from the parents to the offspring.
16
Q
PCR
A
- Denaturation: DNA is heated to approx 94°C to break the hydrogen bonds and separate the strands, forming single-stranded DNA.
- Annealing: The single-stranded DNA is cooled to approx 55°C to allow the primers to bind to complementary sequences on the single-stranded DNA.
- Elongation: The DNA is heated back to 72°C allowing Taq Polymerase to work optimally. It binds to the primer, which acts as a starting region, and begins synthesising a new complementary strand of DNA.
- Repeat: The cycle (steps 1-3) is repeated multiple times to create more copies of DNA.
17
Q
Phagocytosis - 2nd Line of Defence
A
- Pathogen enter via plasma membrane
- Vesicle contains pathogen
- Lysosome fuses with vesicle and then releases lysozyme
- Lysozyme breaks pathogen into fragments
- Fragments presented on MHCII marker
18
Q
Insulin Production
A
- Identify gene of interest coding for Human Insulin
- Same restriction enzyme cut plasmid and gene of interest (Insulin A subunit gene and Insulin B subunit gene)
- DNA ligase for inserting Insulin A subunit gene and Insulin B subunit gene into plasmids
- Antibiotic resistance gene (Amp R and tet R) added to each plasmid.
- Recombinant plasmids inserted into bacteria using heat shock or electroporation to make the bacterial cell membrane permeable to plasmid.
- Bacteria placed on 1 plate with Ampicillin and agar and another plate with tetracycline and agar.
- Surviving bacteria = transformed containing both gene of interest and antibiotic resistant gene.
19
Q
Bacteria CRISPR
A
- After the injection of viral DNA, bacteria cuts the viral DNA segment with the help of CAS 1 and CAS 2 enzyme.
- Viral DNA (protospacer) is inserted into bacterial DNA as “spacer” between repeats (BECOMES CRISPR)
- Spacer is transcribed into gRNA, and gRNA combines with Cas9 to from CRISPR CAS-9 Complex
- Cas9 binds with PAM sequence and gRNA guides Cas9 to make the cut in viral DNA.
20
Q
Artificial CRISPR
A
- Target gene was identified by scientists and the sgRNA was synthesised complementary to target gene.
- sgRNA combines with Cas9 protein to form the CRISPR-Cas9 complex.
- The CRISPR-Cas9 complex is injected into (organism), Cas 9 finds PAM sequence and sgRNA guides Cas9 to make the cut in the target gene on the (organism).
- DNA undergoes repairing/ Target gene knocked out or in
21
Q
Transcription (Nucleus)
A
- RNA polymerase + transcription factor unzips the DNA.
- RNA polymerase binds to the promotor region of the template strand. RNA polymerase starts making complementary sequence of DNA template strand.
- RNA polymerase moves along from 3’ to 5’ direction of template strand and make pre-mRNA having 5’ to 3’ which is antiparallel of template strand of DNA.
- Termination occurs when termination sequence is reached. premRNA is made and detached from template strand.
22
Q
Mammal Characteristics
A
- Fur or hair over their body surface
- Milk-producing mammary glands
- 3 bones in the middle ear
- Warm blooded
23
Q
Primates Characteristics
A
- Opposable thumbs
- A long gestational period
- Binocular vision
- Large brains relative to their body
24
Q
Hominoids Characteristics
A
- Larger and more complex brains
- Y5 molars
- Relatively long upper limbs
- Shoulder joints that permit the arms to be rotated
25
Q
Hominin vs Hominoid
A
Hominin
- S shaped spine
- Barrel shaped ribcage
- Angled femur
- No prehensile feet
- Smaller brow ridge
Hominoid
- Larger brow ridge
- C shaped spine
- Funnel shaped ribcage
- Prehensile hands + feet with opposable thumbs
- Vertically long and narrow pelvis
