B13 Flashcards
1
Q
What is an allele?
A
- A form of gene.
- All genes exist in different versions known as alleles.
2
Q
What is a gamete?
A
- Gametes are sex cells used in reproduction.
- Sperm cell and egg cell in animals.
3
Q
What does homologous mean?
A
- A pair of alleles for a particular gene that are the same.
4
Q
What does heterozygous mean?
A
- A pair of alleles for a particular gene that are different.
5
Q
What is a dominant allele?
A
- The characteristic that is expressed even if you only inherit one.
6
Q
What is a recessive allele?
A
- Genes only expressed when homologous.
7
Q
Genotype definition?
A
- The combination of alleles that you have.
- It is the genes that you inherit.
8
Q
Pheneotype definition?
A
- The expressed ch aracteristics of an organism.
- The expressed genes that are seen.
9
Q
How many pairs of chromosomes are in every human body cell?
A
- 23 pairs
10
Q
What chromosomes do males have?
A
- Males have an X and a Y chromosome: XY
- The Y chromosome causes the male characteristics.
11
Q
What chromosomes do females have?
A
- Females hvae two X chromosomes: XX
- The XX combination allows female characteristics to develop.
12
Q
Definition of Meiosis?
A
- The two-stage process of cell devision that reduces the chromosome number of the daughter cells.
- It makes gametes for sexual reproduction.
13
Q
Differences between mitosis and meiosis?
A
- Mitosis produces 2 daughter cells, meiosis produces 4 daughter cells.
- In mitosis the daughter cells are genetically identical, in meiosis they are genetically different.
- Mitosis is used for growth and repair, meiosis produces gametes for sexual reproduction.
14
Q
Is Cystic Fibrosis dominant or recessive?
A
- Recessive.
- Because is is recessive, people with only one copy of allele (f) won’t have the disorder - they will be a carrier.
- They must be homologous (ff) to be affected by the disorder.
15
Q
Is Polydactyly dominant or recessive?
A
- Dominant.
- Because it is dominant, people with only one copy of allele (P) will have the disorder.
- If you are heterozygous, you (Ff) you will have the disorder.
16
Q
What is a mutation?
A
- A mutation is a random change in an organism’s DNA.
- Mutations change the sequence of the DNA bases in a gene, which produces a ginetic variant (a different form of the gene).
17
Q
Role of DNA in making a protein?
A
- DNA unzips, exposing the gene coding for the protein.
- mRNA (messenger RNA) is made by copying the DNA sequence
- mRNA leaves the nucleus and travels to the ribosome
- The ribosome reads the mRNA sequence in groups of codons
- tRNA (transfer RNA) brings the correct amino acids to match the codons.
- The amino acids are linked together to form a protein.
18
Q
A
