The Genome and its Transmission Flashcards
What is the transcriptome?
The complete set of RNA transcripts.
What is the proteome?
The complete set of proteins produced.
List 4 examples of RNA that are not translated into proteins.
1 & 2 - rRNA and tRNA are involved in the translation of mRNA.
3 - snRNA is involved in modifying other RNA molecules.
4 - miRNA binds to mRNA to inhibit translation.
What is satellite DNA?
Repeated sequences of nucleotides.
What type of DNA is found at centromeres?
Heterochromatin containing satellite DNA.
List 2 differences between heterochromatin and euchromatin.
1 - Euchromatin is transcriptionally active whereas heterochromatin is not.
2 - Heterochromatin stains darker than euchromatin.
What is the function of telomeres?
To protect the end of the chromosome from deterioration or from fusion with neighboring chromosomes.
List 3 roles of repeated sequences of DNA.
1 - Formation of telomeres.
2 - Formation of centromeres.
At which stage of mitosis does chromatin condensation begin?
Prophase.
At which stage of mitosis does spindle assemble outside the nucleus?
Prophase.
What is a kinetochore?
The section of the centromere to which microtubules of the spindle attach.
What is a nucleolus?
When are they present?
- The site of rRNA transcription in the nucleus.
- They appear during interphase and reappear at telophase.
What mediates cytokinesis?
A contractile ring of actin and myosin.
What are chiasmata?
The point on a bivalent at which crossing over and exchange of genetic material occur.
List 4 sources of variation.
1 - Mutation.
2 - Random mating.
3 - Random fertilization.
4 - Crossing over between chromatids of homologous chromosomes during meiosis.
What is a bivalent?
A pair of homologous chromosomes.
List 3 differences between meiosis I and meiosis II.
1 - In meiosis I, homologous chromosomes separate, while in meiosis II, sister chromatids separate.
2 - Genetic recombination (crossing over) only occurs in meiosis I.
What is the name of the male gamete stem cell?
Spermatogonium.
What is a zygote?
A fertilised ovum.
What is a polar body?
A small haploid cell that is formed at the same time as an egg cell during oogenesis, but which does not have the ability to be fertilized.
How might repeated sequences lead to genetic diseases?
- Through slipped mispairing:
- One section of the repeat sequence ‘slips’ to bind to complementary bases further / earlier down the sequence.
