DNA cell Division And Genetics Flashcards
(31 cards)
What is genetic material contained in
Chromosomes in the nucleus of the cell
What are genes
Genes are short sections of DNA that codes for a particular characteristic
Define genome
The entire genetic material found in an organism
What does DNA consist of
2 phosphate and sugar strands
Held together by bases linked my hydrogen bonds
What is a nucleotide
A nucleotide consists of one unit of sugar, phosphate and base
What order can the bases form in?
Adenine-thymine
Guanine-cytosine
How does DNA work?
Coding for different amino acids, which then combine to form proteins.
Bases are read in sequence of 3 (base triplet)
Each base triplet codes for a particular amino acid
Only 1 strand is involved in the coding process
What is protein synthesis
Once amino acids are coded they are linked together to form a protein
Define mitosis
A type of cell division that produces cells genetically identical to the parent cell and to each other
What is mitosis
Cell division, takes place throughout the body
Important for growth and replacing worn out cells and repairing damaged tissue
Ensures new ‘daughter’ cells have exactly the same chromosome arrangement as each other and as the parent cell.
What is meiosis
Occurs in sex organs
Produces gametes
Reduction division as it produces cells with half the number of chromosome as in other cells (haploid)
One cell produces 4 genetically different haploid cells in two divisions
Define meiosis
A type of cell division that produces cells that have half the normal chromosome number
Define independent assortment
A process that takes place during meiosis, in which chromosomes are reassorted in the formation of gametes
Define gene
A short section of chromosome that codes for a particular characteristic. E.g gene for eye colour
Define allele
a particular form of a gene. Brown eyes and blue eyes are different alleles of the eye colour gene
Define homozygous
Describe the situation when both alleles of a gene are the same
E.g both alleles are for brown eyes
Define heterozygous
Describes the situation when the two alleles of a gene are different
E.g one allele is brown eyes and the other is for blue
Define genotype
Paired symbols showing the allele arrangement in an individual
Define phenotype
The outward appearance of an individual
Define dominant
In the heterozygous condition dominant allele overrides the non-dominant (recessive) allele
Define recessive
The recessive allele is dominated by the dominant allele- it only shows itself in the phenotype if there are two recessive alleles
Who is Gregor Mendel
He was a monk who carried out the mono hybrid crosses on peas. Much of our understanding of genetics is based on the work carried out by him.
What did Mendel discover
Certain characteristics in living organisms are determined by factors within the organism (genes)
The genes for a particular characteristic can be present in two different forms (alleles)
The two alleles in an individual separate during gamete formation (meiosis)
An understanding of mono hybrid ratios
Explain sex determination in humans
Humans have 22 normal pairs of chromosomes and one pair of sex chromosomes. The male sex chromosome is XY and the female is XX. They work in the same way as in other genetic crosses. Therefore an equal number of boys and girls are produced
