Inheritance and Genetics Flashcards
What is Inheritance
The transmission of genetic information from one generation to the next
What is DNA
A molecule that stores the genetic information. It’s stored in cells as chromosomes
What are chromosomes
thread-like structure carrying genetic information in form of genes
Define Gene
Length of DNA that contains instructions to build a specific protein. It’s a section of DNA. They have many variants, this are called alleles
Number of chromosomes in a human
46 (23 pairs) unless you have Down syndrome and have 47 (22 pairs and 1 trio) of chromosomes.
Alleles!
There are Dominant Alleles:
- always expressed no matter what
- Written in capital letters
And recessive Alleles:
- Only expressed if there are 2 copies and no dominant allele
- written in lower case
Sex in humans and it’s inheritance
Males have 1 x chromosome and 1 y chromosomes, while females have 2 x chromosomes. It’s always the 23’rd pair which distinguished the sex.
Haploid
cell that contains half the number of chromosomes
Diploid
Cell with full number of chromosomes for it’s specific species
Sperm (male gamete) , Egg (female gamete) and skin cells
sperm cells have 23 chromosomes (haploid)
Egg cells have 23 chromosomes (haploid)
Skin cells have 46 chromosomes (diploid)
Gametes
Reproductive cells of an animal (human)or plant. Human gametes (sperm and egg) are always haploid
Heterozygous and Homozigous
Heterozigous = Different Alleles. Two versions of the same gene. Recessive + Dominant
Homozygous= 2 alleles the same
Dominant + Dominant or Recessive + Recessive
Genotype vs Phenotyve
Genotype = Make-up of an organism in terms of alleles present (not visible to the eye)
Phenotype = Physical and observable characteristics of an organism
Mutation
Change in a gene or a chromosome. Ionising radiation and some chemicals increase the rate of mutation
