DNA Structure
What are the three components of a DNA nucleotide?
deoxyribose sugar, nitrogenous base, phosphate group
What is the purpose of DNA replication?
to create an exact copy of DNA for cell division
What is gene expression?
How the order of bases on DNA produce proteins
What does it mean for a cell to become differentiated?
Specialise into a particular function
What is the genome?
All of the genetic information in an organism
What is the main driving factor of evolution?
Mutations/Natural selection
What holds DNA bases together in the shape of the double helix?
hydrogen bonds
What 4 things are needed for DNA replication to take place?
Primers
Template strand
DNA ligase/polymerase
Free nucleotides
Compare DNA to RNA
Sugars, number of strands, uracil replacement
State the two types of stem cells.
State the function of the non-coding sequences in the genome.
Make up the ribosome and regulate transcription
Describe natural selection
Organisms with selective advantages survive while those with disadvantageous traits die off and do not pass on genetic information. Only well-adapted organisms pass on their genetic information
Explain the term "anti-parallel"
complementary parallel strands that run in opposite directions
DNA is unzipped and unwound during the first stage of DNA replication. What happens immediately after this?
Primers bind to the template strands to provide a location for DNA polymerase to begin working
Describe the functions of tRNA and rRNA
tRNA = creates polypeptide by reading mRNA transcript and adding corresponding amino acids together
rRNA = essential for the production of ribosomes
What is a meristem?
Site of differentiation in plants
Describe the 3 single gene mutations that can occur
Deletion, insertion, substitution
Compare vertical and horizontal gene transfer
Vertical passes info from on generation to another
Horizontal passes info within a generation
Give an example of a prokaryotic cell, as well as how its DNA is organised.
suitable example
As circular plasmids or chromosomes
Describe the formation of the lagging strand
Formed in short fragments as DNA polymerase cannot work in a 3'-5' direction. New primer needed for every fragment
What process occurs after the primary transcript has been formed in the nucleus?
RNA splicing
What are the two fates of stem cells?
Self-renew or used in growth/repair
Describe two types of chromosome mutations
Any correct 2 descriptions
A species of fish living in the Amazon basin has three different variants.
The largest of them is too big to easily navigate the intricate mangrove roots.
The smallest of them is easily hunted.
The medium sized fish is small enough to access hiding spots, but not too small that it can be preyed upon easily.
Over time, the medium size is selected for.
Name this type of selection and draw the correct graph.
Compare DNA organisation in eukaryotes and prokaryotes
Eukaryotes: linear in nucleus, circular in mitochondria and chloroplasts
Prokaryotes: no linear, circular in plasmids and circular chromsomes
Explain the process of PCR
Correct temps
Correct order of events
Explain what happens at the ribosome during transcription
Full process of transcription given
The presence of meristems in plants allow them to do something that animals cannot do. What is this?
Grow continuously throughout their entire life
Explain why duplication mutations are beneficial in evolution
One copy mutates into a trait that gives the organism a selective advantage while the original copy remains unchanged
Compare allopatric and sympatric speciation and provide examples of both.
Sympatric = behavioural and ecological (mating rituals/water salinity)
Allopatric = geographical (canyon, trench etc)