Inheritance Flashcards
Inheritance
transmission of genetic information from generation to generation
Chromosome
A thread-like structure of DNA, carrying genetic information in the form of genes
Gene
Length of DNA that codes for a protein
haploid nucleus
A nucleus contains single set of unpaired chromosomes (sperm or egg cell)
Diploid nucleus
a nucleus containing two sets of chromosomes (body cells)
homologous Chromosomes
The chromosomes which are structurally and functionally similar
Mitosis
Nucleus division giving rise to genetically identical cells (1 cell divides into 2 identical cells, have equal number of chromosomes)
Role of mitosis in growth, repair of damaged tissues, replacement of cells and asexual reproduction
Mitosis is used to create new cells in the body to repair and replace old damaged tissues, as well as allowing growth of organisms and playing a role in Asexual reproduction.
State that during mitosis, the copies of chromosomes separate, maintaining the chromosome number
Mitosis involves splitting of chromosomes, into their two halves, each of which are know was chromatid.
- Before replication occur, chromatid in parent cell replicates to produce identical copies of themselves which pair as chromosomes.
- Chromosomes line up along nucleus
- chromosomes separate so that each identical chromatid is pulled is pulled to opposite poles of the cell.
- Cell membrane constricts in the middle, nucleus is separated as cell splits into two new daughter cells. each cell contain sets of chromatids, which replicates themselves to produce new chromosomes.
Stem cells
Found in embryos of bone marrow, they are unspecialized cells and divide by mitosis to produce daughter cells, which specialise to have variety of functions.
Meiosis
Reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells
-Meiosis is involved in the production of gametes
How meiosis produces variation by forming new combinations of maternal and paternal chromosomes
During meiosis, chromosome Is halved, diploid cell divides to produce 4 haploid cells. As each gamete produced is genetically unique, each offspring will also be unique. Beneficial for species as it produces genetic variation.
Genotype
the genetic make-up of an organism in terms of the alleles present
Phenotype
the observable features of an organism
Homozygous
Having two identical alleles of a particular gene
Pure-breeding
- When two identical homozygous individuals that breed together
- Heterozygous individual will not be pure-breeding
Heterozygous
Having two different alleles of a particular gene
Dominant
an allele that is expressed if it is present
Recessive
an allele that is only expressed when there is no dominant allele of the gene present
Co-dominance
Some alles are co-dominant, meaning neither is recessive, both displayed in the phenotype. Example: Blood groups. Possible groups for blood group is A, B, and O, where A, and B alles are co-dominant, leads to AB blood group. blood group O is recessive, thus is only displayed in phenotype if both parents have O blood groups.
Sex-linked characteristic
- A characteristic in which the gene responsible
is located on a sex chromosome and that this makes it more common in one sex than in the other - Example: colour blindness, recessive characteristic found on X chromosome.
