Genetics Flashcards
Chromosomes, genetics crosses, blood type (33 cards)
Chromosomes
Structures that control each body cell
How many chromosomes does each cell have?
46
How many pairs of chromosome does each cell have?
23 pairs
Why do cells divide?
To multiply for tissue growth or repair
What are cell’s chromosomes like before division?
A cell’s chromosomes double
How many pairs of chromosomes do daughter cells receive?
23 pairs
How does a baby inherit characteristics from each parent?
A sperm and an ovum fuse to produce a fertilised egg with 46 chromosomes, 23 from each parent
How many chromosomes do male and female ‘parent’ cells sex cells have?
46
Sperms and ova have how many chromosomes?
23
A baby’s sex depends on what?
Special chromosomes that it inherits
What shape sex chromosomes do women have?
X - shaped sex chromosomes
Where are sex chromosomes located?
In each body cell of a mother/father
What shape sex chromosome do men have?
One X and one Y sex chromosome
What does a baby inherit from each parent?
Only 1 sex chromosome from each parent
If a baby inherits two X chromosomes what will it be?
Female
If a baby inherits one X and one Y chromosome what will it be?
Male
What do we inherit from parents (characteristically)
Aspects of temperament and physical appearance
Genes
Unit of hereditary passed on from parent to child; units borne on chromosomes
What do genes code for?
Eye colour+ hair colour
How do genes occur? (quantity)
Pairs
What do each pair of genes that we inherit contain?
1 gene from each parent
Two types of gene:
Dominant and recessive
Why might a specific hair colour not appear throughout a generation? (e.g. red hair)
The gene that makes that specific hair colour (e.g., red hair) is recessive and therefore passed through several generations before reappearing.
The dominant gene for another hair colour (e.g. brown) dominates the (e.g red hair) gene.
How does someone resemble their parents more than their grandparents etc. (hair colour for example)?
Families/people of e.g., brown hair unknowingly carry a red - haired gene. Only when an individual inherits two of the recessive e.g., red hair genes they will have red hair
