Genetics Flashcards
Genetics definition
The study of the inheritance of characteristics
Heredity def.
The passing on of features and characteristics from parents to offspring
Species definition
A group of organisms capable of interbreeding and producing fertile offspring
Variation definition
Variation means there are differences between members of the same species
Acquired characteristics
Characteristics developed/learned during life
Eg. Learning to sing, play rugby etc.
Inherited characteristics
Characteristics controlled by gene inherited from parents
Eg. Hair, eyes etc.
Name of bundle of chromosomes
Chromatin
Chromosomes
Thread like structure.
Found in nucleus in pairs
Made up of DNA (genetic info) and protein (holds DNA in place)
Genes arranges along the DNA on the chromosomes
The two types of cells
Sex cells- reproductive cells capable of fertilisation.
Eg. Sperm and egg
Somatic cells- any call except reproductive cells.
Eg. Cheek cells
Chromosome numbers in cells
Somatic: 46 chromosomes- 23 pairs
Sex cells: 23 chromosomes.
Types of chromosomes
Autosomes: non sex determining chromosomes, determines characteristics, 22 pairs
Sex chromosome: determines sex of individual. 2 sex chromosomes (X and Y)
Males: XY
Females: XX
Number of types of chromosomes in different cells
Somatic cells: 44 Autosomes, 2 sex
Sex cells: 22 Autosomes, 1 sex
Meiosis in testes to form sperm
Determines the sex of the individual.
Cells in testes divide by meiosis to produce sperm
X and Y go into different cells
1/2 sperm carry X and half carry Y
All eggs have X
Whichever sperm fuses with egg determines sex.
Sex determination
4 weeks after fertilisation, embryo that contains Y chromosome develops testes ( primary male sex organ). Testes secrete testosterone hormone. Testosterone signals to other cells to develop in male pattern
Gene definition
A gene is a section of DNA found on the chromosome that codes information for the making of specific protein.
Role of genes
Unit of inheritance
Controls the characteristics of an organism
Not everyone has the same version of those genes
More than one type of gene for hair colour
Characteristic definition
Influenced by
The features/ traits that an individual displays
Influenced by genes and environment
Gene expression definition
The way in which information on a gene is coded to make a protein.