Corrections Flashcards
What features do bacterium’s have? Which ones do HIV share?
They have RNA to major proteins, enzymes to catalyse reactions and a cell wall. They have flagellum, mesosomes ( used in respiration ) and are surrounded by a CAPSULE unlike eukaryotes.
HIV does not have a cell wall, but has RNA due to its generic code. It also have enzymes ( eg RNA reverse transcriptase from DNA to RNA ) and is surrounded by genetic matieral called a capsid.
Why can an enzyme sometimes not digest?
It may not have a complementary shape so it cannot bind.
How is ATP reysnthesised, and it’s used?
By ADP and phosphate ion using ATP synthase
Provides energy for other reactions
Adds phosphate to other substances and makes them more reactive
How do we know if a SEM is being used?
3D image and black and white
What is the benefit of the hydrolysis of sucrose for plants?
Produces fructose and glucose
Glucose can be used in respiration to produce ATP for growth
Describe induced fit enzyme model
Before the enzyme binds, active site is not complementary to the shape of the substrate. The shape of the active site changes as the substrate binds to accommodate to the substrate, bending bonds in the substrate.
Conc time graph description for enzyme
Initially, there is a high rate of reaction due to plenty of starch substrates and lots of ESC complexes. Then, the increase in concentration of maltose ( product ) slows down/decreases as starch ( substrate ) is used up.
LEVELS off when no substrate left.
How do you gather data for an absorbance conc graph?
1) use different concentrations of maltose ( eg ) and produce the known concentrations
2) measure the colourimeter value and absorbance of each solution
3) plot this on a calibration curve
Y axis = absorbance
X axis = concentration
DRAW A CURVE
Use the absorbance to find the conc of sample from calibration curve
How do vaccines lead to antibody production?
The vaccine has an antigen. This antigen is displayed on the surface and forms an APC. Specific T helper cells bind to this and are activated. These undergo mitosis to produce B plasma cells. B blasma cells produce antibodies.
How do u use a eyepiece graticule
Measure each stoma using an eyepiece graticule
Calibrate the eyepiece graticule against a stage micrometer
Take a number of measurements
Use the word FEWER and I’m being so fr
Exam q ; why does this antibody only damage nerve cells
The antibody is a protein wirh a specific tertiary structure. It has a binding site which is complementary to only one antigen. The antigen for this antibody is only found on nerve cells, so the antibody only binds to this antigen forming an antigen antibody complex
What makes results not valid?
- no use of statistical test
- weak correlation
- only one study
- missing data ( i,e no information ) so you cannot compare everything
Why do all cells have a mutation?
This is because the cells are all derived from a zygote ( singe cell ). Mitosis occurs produces genetically identical cells so they all have the mutation
Exam Q : gap in pulmonary artery
Oxygenated blood from aorta leaks into the pulmonary artery
Less oxygen delivered to cells, and not enough oxygen for aerobic respiration
Describe the cohesion tension theory of the xylem
Water is lost in the leaf through transpiration
This lowers the water potential of the plant cells
Therefore, water is pulled up the xylem creating tension
Water molecules are cohesive and therefore stick together to form a continuous column/stream
Adhesion forces between water and walls of xylem
How do we form mRNA?
This is by breaking hydrogen bonds to separate DNA strands.
The template strand is used to make mRNA.
Complementary base pairing therefore A U C G
RNA nucleotides join by RNA polymerase
We form mRNA by removing introns
Explain the release of red pigment from beetroot when increased temp
Proteins denature
Damage to the plasma me,brand
There is an increased fluidity
How a sigmoid curve formed?
When the first oxygen molecule binds, causes a change in shape
Therefore allows more oxygen to bind
COOPERATIVE BINDING
Describe trends as significant/large increase
How do structures hve different tertiary stuctures?
Due to different sequences of amino acids and forms hydrogen and ionic bonds in different places
Why do we press on a cover slip?
To spread out cells so light passes through
How could it be ensured the mitotic index was ACCURATE?
Repeat counts to ensure the figures are correct
Examine larger field of views to ensure it is a representative sample
Why do we use controls?
This is to compare the effects of other treatment, and see the effect of the given substance,
How can differences in the primary structure of haemoglobin be used to provide evidence for phylogenetic relationships?
Mutations cause a change in the DNA base sequence. A change in the DNA base sequence causes a change in the sequence of amino acids. If there are more differences in the sequence of amino acids, there is more distantly related.
Closely related mutations have fewer mutations and therefore less differences in sequences of amino acids.
Distant related species have an earlier common ancestor, but closely related species have a recent common ancestor.
Compare and contrast eukaryotic and prokaryotic DNA
Eukaryotic
Bound/ associated with histones
Longer
Linear ( whereas prokaryotic is circular )
Contains introns ( non coding regions )
Similarities
Both have the same nucleotide structure and joined by phosphodiester bonds
Similar DNA in mitochondria and chloroplasts
Reasons why the antibiotic resistance bacteria is more common, and why does percentage of resistant remain constant?
If used in a higher dosage, resistant bacteria is more likely to survive and pass on alleles to offspring for resistance
Bacteria is always reproducing THERREFORE pass on the resistant allele. No selection pressure against resistant bacteria
How can this method be improved for data collection ( biodiversity )?
Collect at more times of year so more points for LOBF
Collect number of individuals so you can calculate index of diversity
Collect from more sites to increase accuracy of mean data
How does an ES complex increase the ROR?
It reduces the activation energy by bending bonds
What do we calculate the index of diversity with?
The number of individuals of each species
How to ensure the diversity of index is representative?
Use a larger sample or random sample
Why does biodiversity decrease when we use larger fields?
Less species
How do arterioles reduce blood flow?
The walls of the smooth muscle contract and this constricts lumen of arteriole
How do you reduce uncertainties?
Use instruments with finer graduations
How does the structure of a protein depends on the amino acids it contains?
The structure is determined by the relative position of the R group.
Tertiary structure determined by interactions between R groups.
What is passive immunity and active immunity? Compare
Passive immunity is introducing antibodies into the body from the outside. They have no memory cells and plasma cells. It has short term immunity as the antibody breaks down. Active immunity is the production of antibodies by plasma cells following exposure to a pathogen. It does involve production of memory and plasma cells. It provides long term immunity as antibody is produced in response to an antigen. Active can take time, passive is fast acting
