B16- Inheritance Flashcards
Define inheritance
transmission of genetic information from generation to generation
Where are chromosomes found?
nucleus of a cell
What are chromosomes made of
DNA
-contain genetic information in form of genes
Define gene
length of the DNA that codes for a protein
Define allele
alternative form of a gene
What chromosomes do female eggs contain
X, X
What chromosomes do male sperms contain
X, Y
What combination of chromosomes does a female zygote contain
XX
What combination of chromosomes does a male zygote contain
XY
What are the chances of the sex for the baby
50%
Describe Haploid Nucleus (2)
Haploid nucleus is a nucleus that contains one set of chromosome
- gametes, sex cells
Describe Diploid Nucleus (3)
Diploid nucleus is a nucleus that contains two sets of chromosomes
- normal human cells (23 pairs)
- has a pair of each type of chromosome
What is Mitosis?
nuclear division creating genetically identical daughter cells
What are the roles of Mitosis? (4)
- growth
- repair of tissues
- replacement of cells
- asexual reproduction
Stages of Mitosis (5)
- Chromosomes create identical copies of themselves (DNA replication)
- similar chromosomes pair up
- Chromatids are pulled apart
- chromosomes separate
- Cells divide (2 daughter cells are made that are genetically identical)
What is Meiosis? (4)
the reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells
What are the roles of Meiosis? (2)
- creates haploid cells by reduction division
- produce genetic variations
What are the stages of Meiosis
- Chromosomes create identical copies of themselves (DNA replication)
- similar chromosomes pair up
- sections of DNA are swapped
- chromosomes are pulled apart
–> first division - chromosomes are divided again (resulting in 4 daughter cells)
–> second division
Define genotype
The genetic make-up of an organism and in terms of the allele present
Define Phenotype
the observable features of an organism
Define Homozygous
having two identical alleles of a particular gene
Define Pure-bred
When two homozygous individuals breed together, the offspring is pure bred
Define Heterozygous
Having 2 different alleles of a particular gene
Define not-pure bred
A heterozygous individual will not be pure-breeding
Define dominant allele
an allele that is expressed if it is present in the genotype
Define recessive allele
an allele that is only expressed when there is no dominant allele of the gene present in the genotype
DD x DD= ?
1- D (dominant)
dd x dd= ?
1- d (recessive)
Dd x Dd= ?
3:1- D (dominant): d (recessive)
DD x dd= ?
1- D (dominant)
Dd x dd= ?
1:1 -D (dominant): d (recessive)
How is a ‘normal’ female identified in a pedigree chart?
empty circle
How is a ‘normal’ male identified in a pedigree chart?
empty square
How is an ‘affected’ female identified in a pedigree chart?
filled in circle
How is an ‘affected’ male identified in a pedigree chart?
filled in square
