Topics to revise Flashcards
(50 cards)
Signal transduction definition
cascade of events in which a message from outside of the cell enters the cell. (Usually second messenger molecules amplify response)
Types of bonds for tertiary and quaternary structures
hydrogen, covalent (disulfide bridges), ionic interactions, hydrophobic interactions
What are first messengers molecules as opposed to second messenger molecules
like the actual message - e.g. hormone
Mitochondrial pathway (5 steps)
- Damage
- Activation of proteins on surface of mitochondrial membrane
- Mitochondrial membrane ruptures
- Caspases are activated and they enter the nuclear pores and destroy DNA
- Dying cells display signals, destroyed by macrophages
Death receptor pathway (6 steps)
- Caspases are activated
- Cells shrink and develop blebs
- Caspases enter nuclear pores and destroy DNA and proteins
- Mitochondria break down
- Fragments bind to receptors on phagocytes and are destroyed
- Phagocytes release cytokines to prevent inflammation and neighbouring cell death
What happens to organelles in apoptosis
generally preserved
Important to remember about drawing a meiosis/mitosis diagram
Need to add like 2n = 4 e.t.c.
Steps of DNA replication
- DNA helicase separates the two strands, exposing the bases
- DNA is antiparallel and semi-conservative, so…
- On the leading strand, primer attaches, then complementary, free DNA nucleotides attach to form a continuous strand in 5’ to 3’ direction - catalysed by DNA polymerase
- On the lagging strand, the new DNA strand is made in pieces called Okazaki fragments, which are joined together by DNA ligase
Basic remember prompts for DNA replication (4 points)
- DNA helicase separates DNA,
- DNA is antiparallel and semi-conservative, so…
- On leading strand primer attaches, complementary free DNA nucleotides attach to form strand - catalysed by DNA polymerase
- On lagging strand, made in pieces 3’ to 5’ called Okazaki fragments that are joined by DNA ligase
Leading strand is what prime to what prime
3’ to 5’
Lagging strand is what prime
5’ to 3’
What enzymes are involved in DNA replication
DNA helicase, DNA polymerase, DNA ligase
Chiasma
Point of crossing over
Ratio of test cross with heterozygous
1:1:1:1
Offspring produced by linked genes that are different from parents name
Recombinant offspring
If you have to work out which letters go on top for linked genes,
do a cross
Steps for genetic engineering (5)
- Isolation of gene
- Insert gene into vector
- Transfer vector to organism
- Transformation of organism
- Selection of GMO
Southern blotting
separates DNA
Polymerase Chain Reaction Steps
- 94 degrees, to dentature
- 50 degrees and add primer, to hybridise two strands
- 72 degrees, DNA polymerase initiates DNA synthesis, free and complementary base nucleotides
Natural selection steps (5)
- Genetic variation exists in a population resulting in phenotypic variation within the population.
- In a changing environment, organisms with the favoured phenotype will have an improved chance of surviving and reproducing over those of less favourable phenotypes.
- Hence more offspring will posses the favoured characteristics
- And their frequency (and that of the alleles) within the population will increase across generations
- In time, evolution of a new species may occur.
Selective agents definition
Agents that ‘select’ for or against particular organisms surviving and producing offspring.
Darwin’s beliefs
different genotypes hence phenotypes, struggle for survival due to selective pressures, best suited will produce more, new variations can result in evolution
Adaptive radiation is what kind of evolution
divergent evolution
maybe read about it
Molecular clock definition
Uses fossil evidence and rates of molecular change to deduce the time in geological history when two species diverged.
