Genetics Flashcards
(44 cards)
What is fertilization?
The fusion of the nuclei of the male and female gametes, which forms a zygote
What are Gametes?
Specialized sex cells
Usually 2 kinds “male” & “female”
Each gamete has half the number of chromosomes as the parent cell from which it came
What is a zygote?
A single cell formed by fusion of gametes at fertilization
What is a somatic cell?
AKA BODY CELLS!!!
All cells in the body other than those that produce gametes
Every species of organism has certain number of chromosomes in it’s somatic cells
What are homologous chromosome?
A pair of similar chromosomes , similar in size, shape, and genetic content
What are sister chromatids?
Exact replicas
Another name for body cells?
Somatic cells!!!
How many pairs of chromosomes does your body have?
23 for each homologous pair one chromosome comes from each parent
Autosomes? And sex chromosomes?
Chromosome pairs 1-22
X and Y determine gender in mammals
Body cells are?
Diploid!
Have 2 copies of every chromosome (2n)
Half chromosomes come from each parent
46 in humans
Gametes are?
Haploid!!
Have 1 copy of every chromosome
Have 22 Autosomes and 1 sex chromosome
23 in humans
What is major in meiosis?
It makes diploid cells into haploid cells
Why is making diploid cells into haploid important? Explain why it’s important?
It’s important because if you don’t a person will have extra chromosomes resulting in defects
What happens in meiosis 1?
Homologous chromosomes seperate
What happens in meiosis 2?
Sister chromatids are separated
What happens in Prophase 1? Why is it important?
Important because homologous chromosomes pair up and form tetrad
Increases variety!!
May tangle leading to !!crossing over!!- exchange of chromosomal segments
Anaphase 1
Disjunction occurs— homologous pairs seperate(pulled to opposite poles)
Non disjunction– when the homologous pairs don’t seperate
What are the advantages of sexual reproduction?
Variation
Parents and offspring not exactly alike
Environmental change + variation– possibility of survival of the species
Genetics? Traits?
The study of biological inheritance patterns and variation
Distinguishing characteristics that are inherited
In heterozygous individuals this is not seen?
Recessive allele
What is an allele?
Different forms of a gene for a particular trait
Genotype? Phenotype?
The genetic makeup of an organism (Tt ,tt)
The physical trait an organism develops as a result of it’s genotype (tall or short)
Larry the lizard has long legs..Phenotype or genotype?
Phenotype
Timothy the turtle is heterozygous for crazy eyes…phenotype or genotype?
Genotype