Patterns of inheritance Flashcards
What does DNA stand for ?
deoxyribonucleic acid
What is the job of DNA
Stores genetic information for inheritance
Where is DNA found in cells
Discrete packages of DNA
How many chromosomes are there in each “normal “ human cell
48
Why is DNA described as being a double helix
DNA is made up of two strands
The two strands are held together by hydrogen bonds
What does the information within DNA code for ?
The sequence of amino acid in protein
How do sperm egg cells differ from other human cells ( with regard to DNA ) and how is this useful ?
They contain half each of DNA of “ normal cells “
So that when they fuse to form a zygote the new cell formed will have the full amount of DNA
What are genes
They are sections of DNA which code for a single protein
These determine particular traits
How does the combination of chromosomes in the cells within a human arise
The combination consists of half the chromosomes of each parent
Define genetics
The study of inheritance of traits and the resulting phenotypes which could appear
What are alleles ?
A variant or different from of a particular gene eg
Hair colour has the following alleles , red , blonde , brown and black
Define mutation
Random changes to the genetic code in DNA. The bases in DNA are A , C , T and G
What does fertilisation mean ?
The fusion of a sperm and an egg to form a zygote. The zygote them develops into a embryo.
What are sex chromosomes
The 23rd pair of chromosomes in humans
What sex chromosome combinations result in the different sexes
Males XY
Females XX
