B12 - Reproduction Flashcards
What is asexual reproduction?
No gametes (sex cells) are involved. All genetic info comes from 1 parent. So there is little VARIATION
How are clones formed?
By mitosis
What are identical copies called in asexual reproduction?
Clones
What is sexual reproduction?
Fusion of gametes (sex cells). Mixing of genetics. So offspring show variation
How are gametes formed?
By meiosis
What does meiosis do?
Produces gametes in which chromosome number is halved. When 2 gametes fuse the whole chromosome is restored
What are the sex cells in plants?
Egg cells + pollen
How many gametes are formed in meiosis?
Genetic material is copied then cell divides twice to form 4 gametes, each with single set of chromosomes
What is the genome of an organism?
It’s entire genetic material
What is DNA?
Polymer made up of 2 strands of DNA
What is a polymer?
Very long molecule
What is a gene?
Code for protein
How does the human genome help scientists and doctors?
- Helps understanding and treatment of inherited diseases
- Tracing human migration
What is an allele?
Different forms of a gene
What is the phenotype?
Characteristics
What is the genotype?
Genetic makeup
What is homozygote?
Both alleles are the same (DD or dd)
What is heterozygote?
Both alleles are different (Dd)
When is a dominant allele expressed?
In the phenotype, even if only 1 copy is present
When is a recessive allele expressed?
Only if 2 copies are present
How many pairs of chromosomes do humans have?
23 pairs
What letters are males and what are females?
Female: XX
Male: XY
What is polydactyly?
Genetic condition. Baby is born with more fingers or toes.
What causes polydactyly?
Dominant allele. It’s inherited.
