Paper 1 Corrections Flashcards
What are the stages of the lytic pathway?
Attachment – The virus attaches to the surface of a host cell.
Injection – It injects its genetic material into the host cell.
Replication – The host cell’s machinery is used to make new viral components (e.g., proteins and genetic material).
Assembly – These components are assembled into new virus particles.
Lysis – The host cell bursts (lyses), releasing the new viruses.
Spread – The new viruses go on to infect other cells, repeating the cycle.
How does a gastric band reduce the risk of developing diseases like cardiovascular disease?
A gastric band reduces the volume (or size) of the stomach
So the person feels full sooner and eats less food
This leads to weight loss, which reduces risk factors such as:
High blood pressure
High cholesterol levels
Type 2 diabetes
All of which lower the risk of cardiovascular disease
When cells loose water what is it called?
becoming plasmolysed
what color does iodine turn in the presence of starch?
blue / black
Immune response / memory lymphocytes
Explain how an adult develops immunity to a toxin
Adult was previously exposed to the toxin
This stimulated an immune response witch produced B-lympocytes to destroy the toxin
Memory lymphocytes were formed
On re-exposure, these memory cells allow a faster immune response
What are the advantages of using adult stem cells ( reprogrammed to act like embryotic) in medicine?
Stem cells have the potential to **produce any cell type **
Their use eliminates the need for embryonic stem cells.
There’s a reduced chance of patient rejection when using their own cells.
They can be used to treat currently incurable conditions by replacing faulty cells
What key processes occur during interphase in the cell cycle?
DNA is replicated
Production of cell components (e.g., proteins, organelles)
Cell growth and metabolic activities
How do you obtain a set magnification
eyepeice lens x10
objective lens x the rest
Why do pentadactyl limbs suggest that certain species evolved from the same ancestor?
Same structure of bones
unlikely to have occured more than once during evolution - common ancestor had pentadactyl limb
How does genetic analysis provide evidence for evolution?
Allows us to compare the genes of different organisms
Closely related organisms have more similar gene sequences, showing evolution from a common ancestor
when talking about genetic inheritance / mendel, what key words should you use?
Homozygous/heterozygous
Recessive/dominant
-> If 1 or 2 alleles are needed for expression
Punnet stats
Why is a certain variable kept the same in this experiement?
As a control variable
so results can be compared + whatever it would affect
What does increasing the concentration of substrate do?
Increasing the concentration of substrate increases the rate of reaction
* provides more substrate
* increases collisions
* more active sites occupied
* forming more enzyme-substrate
complexes
* product is formed faster
If a substrate concentration is increased, and the RofR does not, whats going on?
The substrate is no longer the limiting factor as all active sites are occupied
What are the positives and benefits of producing drugs from genetically modified yeast cells instead of plants?
Benefits
-> increasing yield /it can be produced in a
shorter time period
-> production is cheaper/easier to extract
-> takes up less space than growing plants
-> yeast growth is not weather dependent
Risks
-> The painkillers may not be
identical/as effective (1)
-> Concerns over GM organisms
entering environment (1)
Variation in DNA sequence
DNA has 4 different bases
* changes in the DNA are mutations
* results in different alleles for these genes
* affects the phenotype / produces variation
Genome
Outcome of DNA sequencing for individual
- identify genetic diseases
- identify the risk of developing diseases
- impact of knowing that a disease could develop
- allow the individual to modify their lifestyle to reduce
risk
