B1 - You And Your Genes Flashcards
How many chromosomes are there in a gamete?
23 chromosomes
What is an allele?
A variation of the same type of gene.
Where are chromosomes found within a cell?
In the nucleus
True or false - in humans, chromosomes are usually found in groups of four?
False - they are found in pairs
How do genes control the different characteristics we develop?
They code for the proteins which structure our features and therefore the characteristics we display
What do the words ‘genotype’ and ‘phenotype’ mean?
Genotype = All of the genes in an organism Phenotype = The genes the organism displays
Is a person’s weight determined by genes, the environment or a combination of both?
Both
Name the two types of sex cell.
Egg cells and sperm cells
How many chromosomes are found in sex cells? And what are these cels called?
23 chromosomes
Gametes
Why do most children look a bit like both of their parents but not identical to either?
Because you receive half of your genes from both parents
What is the difference between homozygous and heterozygous?
Homozygous = both your alleles for that particular gene are the same e.g. AA Heterozygous = your alleles for that particular gene are different e.g. Aa
What sex chromosomes do human males have?
X and Y
How does a gene on one of the human sex chromosomes cause embryos to develop into males?
Because it codes for the protein which develops the testes and the rest of the male reproductive system.
Is the allele for cystic fibrosis dominant or recessive?
Recessive
What are the symptoms of cystic fibrosis?
- thick, sticky mucus
- difficulty breathing
- difficulty digesting food = often small and skinny
- chest infections =painful coughing