Chapter 16:chromosomes,genes and protein Flashcards
(23 cards)
Define chromosome
a length of DNA,found in the nucleus of a cell;it contains genetic information in the form of many different genes
Define DNA
a molecule that contains genetic information,in the forms of genes,that control as the proteins that are made in the cell
Define gene
a length of DNA that coded for one protein
Define alleles
alternative forms of a gene
Define alleles
alternative forms of a gene
where are chromosomes located
In the nucleus of the cell
Define inheritance
The transmission of genetic information from generation to generation
How many chromosomes to humans have
46 chromosomes (23 pairs)
Define mitosis
nuclear division giving rise to genetically identical cells
What is the role of mitosis
-It helps in growth,repair of damaged tissue,replacement of cells and asexual reproduction
-mitosis produces new cells to make the body grow larger cells or replace damaged cells
What are the two identical threads called I’m chromosomes
Chromatids
What is the point where the chromatids are held together
Centermere
How does mitosis happen
The copies of chromosomes seperate,maintaining the chromosome number in each daughter cell
Why is meiosis recurred
Meiosis is involved in the production of gametes
Define meiosis
Reduction division in which the chromosome number is halved from the diploid to haploid resulting in genetically different cells
Define homozygous
Having two identical alleles of a particular gene (GG or gg)
Define heterogenous
Having two different alleles of a particular gene (Gg)
Define genotype
The genetic makeup of an organism in terms of the alleles present (GG)
Define phenotype
The observable features of an organism
Define dominant allele
an allele that is expressed if it is present (G)
Define recessive allele
an allele of that is only expressed when there is no dominant allele of the gene present (g)
Define codominace
alleles that’s re both expressed in the phenotype when they are both present
Example of codominance
the inheritance of the ABO blood group antigens in humans is a good example of codominance
