Evolution Flashcards
What can swapping of genes change for virus strains? [3 marks]
- Specificity of the virus
- How easily it can spread
- What species it can infect
What is the definition of evolution? [1 mark]
The accumulated, heritable changes within a population.
Why does E. coli evolve to be able to grow in citrate in aerobic condition? [1 mark]
- Citrate promoter is usually off
- RNK promoter regulates gene for regulator of nucleoside diphosphate kinase (RNK) which is on in the presence of oxygen.
- RNK promoter can be duplicated near the citrate gene and control it.
Small mistakes from DNA replication [4 marks]
- Duplication
- Insertions
- Deletions
- Base substitution
Big mistakes from DNA replication [5 marks]
- DNA duplications
- Chromosome rearrangements
- Deletions
- Viral insertions
- Insertion of transposable elements
How do changes in genotypes arise? [4 marks]
- Natural selection
- Genetic drift
- Gene flow
- Applied selection
Where are the highest amount of mutation found? [1 mark]
Non coding regions
What does systematics deal with? [1 mark]
Classifying living things.
What is taxonomy? [1 mark]
Naming of groups of organisms (taxa).
What is classification? [1 mark]
Arranging taxa into an ordered, hierarchical system.
What is phylogeny? [2 marks]
- Determination of ancestral relationships of organism.
- Determination of organisms’ evolutionary history.
How can rock be dated? [1 mark]
Measuring the decay of naturally occurring isotopes.
Why can’t sedimentary rock be used for dating? [1 mark]
The rock wouldn’t necessarily be the same age as the fossil.
How are fossil dates bracketed? [2 marks]
- By the age of surrounding igneous rock.
- Because igneous rock is fixed and cannot have been formed before or after.
What is the definition of half life? [1 mark]
The period of time taken for radioactivity to decrease by half.
What determines the date of a fossil in radiometric dating? [1 mark]
The ratio of parent to daughter atoms.
What are the requirements for radiometric dating? [6 marks]
- Rate of radioactive decay is constant.
- Not affected by temp, pressure, chemicals or electromagnetic fields.
- System must be closed.
- Parent and daughter nuclides cannot leave or enter material after its been formed
- No intrusion of the rock.
- No contamination.
What happened in the Cambrian explosion (around 525 million years ago)? [1 mark]
The rapid appearance and disappearance of complex organisms.
What are homologous structures? [2 marks]
- Structures that are similar by descent e.g. tetrapod limbs.
- From a common ancestral version.
What are two types of molecular homology? [2 mark]
- Paralogs: Genes from the same organisms (via duplication).
- Orthologs: Genes from different organisms (common ancestor).
What are analogous structures? [2 marks]
- Structures that are similar by function e.g. wings.
- They are produced by convergent evolution.
What are Hox genes?
They are a group of highly conserved genes that control the body plan of organisms.
What is the RNA World hypothesis? [1 mark]
A hypothesis that states that early life came from self-replicating, self-catalysng ribozymes e.g. tRNA.
Why is DNA more stable than RNA? [2 marks]
- DNA has thymine instead of uracil.
- Thymine has a greater resistance to photo-chemical mutations than uracil.
What is the structure of DNA in bacteria and archaea? [2 marks]
- Not contained in a nucleus
- Circular DNA
Which domain has an RNA cap and poly A tail? [1 mark]
Eukaryote
What is the size of ribosomes in bacteria and archaea? [1 mark]
70S
What is the tRNA initiator in bacteria? [1 mark]
Formyl-methionine
What is the tRNA initiator in archaea and eukaryotes? [1 mark]
Methionine
Which domain has rifampicin-sensitive (antibiotic senstitive) RNA polymerase? [1 mark]
Bacteria
Which domains have histones? [2 marks]
- Archaea
- Eukaryotes
What do mitochondrial genomes bare similarity to? [1 mark]
Rickettsia prowazekii (Typhus bacterium)
What happens to lost genes from plastids (usually in plant cells)? [1 mark]
They are taken up and incorporated into nuclear DNA.
What are the basic processes of multicellularity? [4 marks]
- Spatial organisation
- Change in form
- Growth
- Differentiation
What family of proteins are used in eukaryotes to detect light? [2 marks]
- Opsins (homologous)
- G protein coupled receptors that convert light to nerve impulses
What happens when there’s mutations to the orthologous Pax6 gene (eyeless) in humans and mice? [2 marks]
MICE: causes smalleye
HUMANS: causes aniridia
What is ectopic expression? [1 mark]
Abnormal gene expression where the gene is not usually expressed.
What are hCONDELs and where do they mostly occur? [2 marks]
- Sequences that are conserved in other animals but deleted in humans.
- Mostly in places where steroid hormone receptor activity occurs.
What happens in the hCONDEL near the androgen receptor gene? [2 marks]
- Loss of enhancer in humans
- Whiskers and penile spine is not expressed in humans.
What happens in the hCONDEL near the androgen receptor gene? [2 marks]
- Loss of enhancer in humans
- Whiskers and penile spine is not expressed in humans.
What causes changes in mtDNA and the Y chromosome? [1 mark]
Random mutations over time.
