chromosomes and genes Flashcards
what is chromotin
within the nucleus of a cell DNA is loosely packaged (for easier access) this known as chromatin
what is chromosome
when a cell prepares to reproduce the DNA condenses into a tight package known as a chromosome
when are chromosomes visible within a nucleus
when the DNA is about to reproduce
how many copies of genetic material may a cell contain
one or two depending on where they are in the life cycle
One copy = single stranded chromosome
Two copies = double stranded chromosome
what is a chromatid
Each individual copy of the genetic material within a chromosome is called a chromatid
how many chromatids does a chromosome have
Single stranded chromosome has one chromatid
Double stranded chromosome has two chromatids
what is a centromere
the point where two chromatids join is known as a centromere
what is the difference between a chromosome and a chromotid
a chromatid is one of the two identical halves of a chromosome that has been replicated in preparation for cell division
what are genes
Small sections of DNA are called genes
Genes determine the characteristics of an organism
what gives an individual their unique characteristics
The different order in which the nitrogenous bases are arranged within a gene are what gives an individual their unique characteristics
how are genes passed down
Genes are passed down from parents to offspring
This is why family members often share similar traits
most cells in the human body contains ____ chromosomes
46
23 come from the father, 23 from the mother
what are homologous pairs
All 46 chromosomes in a human are organised into pairs, known as homologous pairs
what is a karyotype
A pictorial representation of all of the chromosomes in a cell is called a karyotype.
It shows the chromosomes in homologous pairs
what are autosomes and what does it determine
The first 22 pairs of chromosomes are called autosomes and determine the general characteristics and function of an organism
