Biology 4-(genes) Flashcards
Different versions of the same gene are called what
Alleles
Changes in an organisms dna leads to what
New alleles being formed
Body cells have how many chromosomes
23 pairs
How do body cells replicate
Mitosis
What’s the purpose of mitosis
To replace/replicate and to produce identical cells
Plants reproduce by mitosis which is called what
Asexual reproduction
Gametes have how many chromosomes
23 (half the number)
Body cells are what type of cell
Gametes are what type of cell
Diploid
Haploid
Where does meiosis take place in humans
What happens
Ovaries/testes
One parent cell makes 4 gametes
What causes sex organs to delveop
The lack of Y chromosome containing a specific protein
Or the Y chromosome being present contain the specific protein
How many alleles does gametes contain
One allele
Cystic fibrosis produces thick mucus where
Airways and pancreas
For a child to have CF, what must both parents be
Must be carriers
Or have CF
Polydactyly is caused by what
Dominant allele
Extra toes/fingers
Huntington’s disease is caused by what
Dominant allele
Any parent that is heterozygous with Huntington’s / polydactyly will be what
Will have the disorder
Plant cells don’t lose what
The ability to differentiate into other cells
How do genetic engineers cut out a DNAs useful gene
Using restriction enzymes
What do restriction enzymes leave on the DNA it’s just cut?
Sticky ends
What is used as a vector to place prepared DNA from restriction enzyme into the new host
Plasmid from bacteria dna
What joins sticky ends together
Ligase
What two gene therapies could be sized to cure genetic disorders
Changing the genes in body cells
Changing the genes in gametes
What are the 2 different causes of variation in a species
Genetic variation
Environmental variation
Combining of genes from two parents causes what
Name 2 examples of characteristics changed by genes in animals
Genetic variation
Eye colour /blood group / inherited disorders
Environmental variation example in animals and in plants
Losing a toe
Change in leaf colour from sun
Most characteristics are due to what
Genes and environment
Mutations can be beneficial and for rise to what (eg)
Evolution
Resistance to antibiotics
The genetic code is degenerate
What does this mean
Several codons can code for the same amino acid
