Genetics Flashcards
Describe the structure of DNA?
- double helix
- sugar phosphate backbone
- complementary bases help together with hydrogen bonds
What are the pairs of bases in DNA and what type of bond holds them together?
A-T = 2 hydrogen bonds
C-G = 3 hydrogen bonds
What are 4 differences between mitosis and meiosis?
MITOSIS
- genetically identical
- diploid/ body cells
- 2 daughter cells
- asexual
MEIOSIS
- not genetically identical
- haploid/ gametes
- 4 daughter cells
- sexual
What is an allele?
Different forms/ version of a gene
The sequence of bases in different alleles may vary by one or two
bases, what causes this?
Mutation
What are the medical benefits of knowing the entire human genomes?
- diagnosis of genetic diseases
- comparison between individuals (paternity)
How many chromosomes are there in a human body cell?
46 (diploid)
How many chromosomes are there in a sperm and egg cell?
23 (haploid)
Why do gametes (sex cells) only contain half the number of
chromosomes?
You inherit half your DNA from each parent
What are the male and female sex chromosomes?
MALE - XY
FEMALE - XX
What are dominant alleles?
H
What are recessive alleles?
h
How many of the allele would you need to have a disease caused by
a recessive allele?
2 - hh
What would be the possible genotypes of someone that has a
dominant disease?
Hh or HH
Why is there a greater probability of inheriting a dominant disease
compared to a recessive disease?
With a dominant disease you only need to inherit the faulty allele from one parent
Recessive diseases you need two recessive alleles, (both parents)
