Inheritance II Flashcards
Somatic chromosomes
One chromosome from mother and one from father
Gene
A small region of DNA that contains genetic information for making a protein
Two of the same chromosome
Homologous pair (contain the same genes)
Female chromosomes
XX
Male chromosomes
XY
Mitosis steps
Interphase Prophase Prometaphase Metaphase Anaphase Telophase Cytokinesis IPPMATC
Interphase (mitosis)
1st step
DNA is copied and some duplicated
Chromosomes aren’t visible
Prophase (mitosis)
2nd step
Chromosomes condense
They are now visible
Consist of 2 chromatids
Prometaphase (mitosis)
3rd step
Nuclear membrane disappears
Spindle fires form
Metaphase (mitosis)
4th step
Chromosome align at the equator
Anaphase (mitosis)
5th step
Spindle fires pull the chromatids apart to opposite ends on the cell and they are now chromosomes again
Telophase (mitosis)
6th step
A new nuclear membrane formed around each set of chromosomes
Cytokinesis (mitosis)
7th step
The cells start to divide and two new genetically identical daughter cells are formed
Where does mitosis happen
All body cells expect sex cells
What is the product of mitosis
2 genetically identical sister cells (haploid)
What happens to the chromosome number in mitosis
Stays the same
In mitosis are the parent and daughter cells the same
Yes
What is the purpose of mitosis
Making cells for growth a repair
What is the purpose of meiosis
Producing sex cells
Where does meiosis take place
Sex organs
What happens to the chromosome number in meiosis
It’s halved
Are parent and daughter cells identical in meiosis
No
What is the product of meiosis
4 diploid cells
Interphase I (meiosis)
1st step
Normal diploid cells
Interphase (meiosis)
2nd step
Chromosomes are copied
Prophase I (meiosis)
3rd step
Homologous chromosomes pair up
Prophase (meiosis)
4th step
Crossing over occurs
Metaphase I (meiosis)
5th step
Chromosome pairs align at equator
Anaphase I (meiosis)
6th step
Chromosomes move to opposite ends of the cell
Telophase I (meiosis)
7th step
New nuclear membranes around each nucleus
Cytokinesis I (meiosis)
8th step
Cytoplasm divided
Metaphase II (meiosis)
9th step
Chromosomes align at equator of cell
Anaphase II (meiosis)
10th step
Chromatids move to opposite ends of cell
Telophase II (meiosis)
11th step
New nuclear membranes are forms around each nucleus
Cytokinesis II (meiosis)
12th step
The cytoplasm divides
Name of the cell when sperm fertilises egg
Zygote
How does a zygote develop into an embryo
Cell division
Diploid cell
Cell with 2 sets of chromosomes (46- full set)
Haploid cell
Cell with one set of chromosomes (23- half set)
Advantage of meiosis
Allowed variation
Genotype
Your genetic makeup- all of the alleles present in the cell nucleus
Homozygous
2 identical alleles (BB or bb)
Heterozygous
2 different alleles (Bb)
Phenotype
The characteristic that is shown from a genotype
Codominance
Both alleles contribute to the phenotype
Pedigree tree
Family tree which records the characteristics and genotypes in a family
Where do new alleles come from
Mutation
Most mutations are
Harmful
Some mutations are
Neutral
Very few mutations are
Beneficial
What’s are the different type of mutations
Gene and chromosome
What’s a mutation
Change in genetic code
Describe meiosis
Chromosomes replicate
Condense
Exchange genetic material
Chromosomes half
What’s is cystic fibrosis
Cell membrane disease- need 2 recessive alleles from parents
4 bases in DNA
Adeline
Thymine
Guanine
Cytosine
Backbone of DNA
Made of deoxyribose(sugar) and phosphate