Lecture 2 Flashcards
What is the size of a viruses genome?
Varies from 10-100 kilobases of DNA
What is an operon?
In prokaryotes set of genes that are needed at the same time
/ need to be read together
What is the size of a prokaryotic genome?
Varies from 112,000 base pairs to 12Mb.
Eukaryotes typically have the largest genome of …
150 gigabases to 3megabases
organised into chromosomes(1-1600; usually 10-100)
Paramecium is a … and has two nuclei. What are they called and what is their function.
Paramecium is a protist.
It has a macro nucleus - for protein transcription and translation for the “working genome”
And a micronucleus - germline genome, passed on in sexual reproduction.
Ploidy varies between species. Give some examples.
Dog rose is pentaploid - four copies of chromosome from mother, one from father
Polyploid - food plants -triple or more their chromosomal content.
Bees, ants and wasps - females are diploid, males haploid
Define Karyotype
The number of chromosomes in a cell
Do prokaryotes have plasmids?
Plasmids are an optional extra
Protist genomes?
Protists are understudied - could have a genome larger than the human genome
What is ploidy?
The number of chromosomes occurring in the nucleus of a cell
Define karyotype
The number of chromosomes in a cell
Their collection of chromosomes
What is parthenogenetic?
asexual reproduction of embryos without fertilisation by a sperm.
Determination of sex differs between species.
Humans (mammals) use the xy chromosome system (xx= female, xy = male)
Birds and butterflies - WZ system (wz female, zz male)
Platypus has 10 sex chromosomes
Clown fish change sex over time.
What is environmental sex determination?
The organism develops to be male or female, but the environment can trigger which sex.
- nutrients
- temperature
Examples of environmental sex determination
Crocodiles - the heat at which the egg incubates determines sex
Green spoon worm - Female if larva falls on sand
Male if lands on a female
Female breaths them in and they become a part of the organism
