Flashcards in 3. Karyograms Deck (14):
How many chromosomes do prokaryotes have? How many do eukaryotes have? What do they do?
- pro: 1
- eu: different chromosomes that carry genes
How many chromosomes in humans? What do they do?
23 different chromosome types each of which carries a different group of genes
Define 'homologous' in terms of chromosomes.
chromosomes of one particular type - same genes in same sequence, but different alleles of those genes
different forms of a gene
The number of chromosomes is a.....species
- characteristic feature of members of a species
When quoting numbers of chromosomes a species has, what number is usually quoted?
the diploid number - how many chromosomes are present in normal body cells
Give 5 examples and diploid chromosome number.
Homo sapiens (humans) - 46
Pan troglodytes (chimpanzee) - 48
Canis familiaris (dog) - 78
Oryza sativa (rice) - 24
Parascaris equorum (horse threadworm) - 4
What sort of nucleus do most plant and animal cells have? What do some cells have?
- diploid nucleus - nucleus contains pairs of homologous chromosomes
- haploid nucleus - only has one chromosome of each type
Name two cells that have haploid nucleus'?
gametes such as sperm and egg cells of humans
How is a diploid nucleus cell formed by two gametes?
gametes such as sperm and egg cells fuse together during fertilisation and produce one diploid cell - a zygote
Which pair of chromosomes determines your sex in humans? How?
the 23rd pair:
- two types of sex chromosome: X and Y
- XX: female
- XY: male
the number and type of chromosomes present in a cell or organism
What is a karyogram?
- a photograph or diagram in which the chromosomes of an organism are shown in homologous pairs of decreasing length