Genetics Flashcards
The structure of DNA.
Double helix
- Base (hydrogen bonded); Adenine, Thymine, Guanine and Cytosine
- Phosphate
- Deoxyribose Sugar
What are the nucleotides?
- Phosphate
- Deoxyribose sugar
- Nitrogen base
What forms the upright parts of the double helix ladder?
Alternating sugar and phosphate units.
What does DNA stand for?
Dexoyribose Nucleic Acid.
What is genetics?
The study of heredity.
What is heredity?
The passing of traits from parents to offspring.
What do genes make?
Protein.
What are true breeding plants?
Plants that always create plants that look like themselves.
What is a hybrid?
The offspring of two plants of animals of different species or varieties.
What is genetic manipulation?
The process of gene splicing to create recombinant DNA and enables cells to be genetically modified.
What are the 7 steps of genetic manipulation?
- Plasmids are removed from the bacterium
- The plasmids are cut using an enzyme
- DNA is removed from the cell
- DNA is cut to isolate the gene using an enzyme
- The gene is inserted into plasmid to form recombinant DNA
- The recombinant is put into a bacterium
- The bacterial calls grow and divide to produce many copies of the introduced gene
What are enzymes?
A protein manufactured by a cell and is a catalyst in various biological functions.
Define recombinant DNA.
DNA which has been modified by adding DNA from another source.
Define DNA ligase.
An enzyme which joins DNA strands together.
What are restriction enzymes?
An enzyme produced by certain bacteria.
What is the restriction site?
Where the DNA has been cut.
What is plasmid?
The ring of DNA found in bacteria.
What is the donor DNA?
An organism which supplies living tissue to another organism.
What is gene therapy?
When the defective gene is replaced with a normal gene.
What is gene testing?
Replacing genes with diseases for normal genes to prevent or cure a disease.
What are chromosomes?
Thread-like structures in the nucleus, composed of DNA and proteins; contains the genetic information in the form of genes.
What is a gene?
A section of DNA the carries the genetic information for a particular characteristic.
What is an allele?
Alleles are different forms of the same gene.
Mendal’s 1st law
- Alleles are inherited as one from each parent.
- In the heterozygous state, the dominant trait is expressed phenotypically, the recessive trait is passed from carrier to offspring genotypically
Dominant genes/characteristics
The characteristic that is expressed in the heterozygous.
Recessive genes/characteristics
The characteristic the remains hidden in the heterozygous condition.
Mendal’s 2nd law
Different gene pairs assort independently in gamete formation (meiosis) - this is only true in some cases
Modes of Inheritance
- Inheritance patterns describe how a disease is transmitted in families.
- Help to predict the recurrence risk for relatives.
- Inheritance patterns for single gene disorders are classified based on whether they are autosomal or X-linked and whether they have a dominant or recessive pattern of inheritance.
What is an autosome?
All the chromosomes in a cell other than the sex cell chromosomes.
Sex linked characteristics
Sex linkage is linked to the gender of the individual. Usually such genes are found on the X chromosome.
What is a punnett square?
The Punnett square is a diagram that is used to predict an outcome of a particular cross or breeding experiment.
Define homozygous
Having two identical alleles on homologous chromosomes.
Define heterozygous
Having two different alleles on homologous chromosomes.
What are homologous chromosomes?
Chromosomes with genes for particular characteristics at the same location.
What is a geneotype?
The genetic information carried by an individual.
What is a phenotype?
The observable of the individual; the way genotype is expressed.
What is a pedigree?
A diagrammed family history which gives information on the mode of inheritance of a disease and the recurrence risk, that is, the probability that the offspring of a couple will express a genetic disease.
What is the diploid number?
The number of chromosomes in body cells; two sets or 2N.
What is meosis?
The cell division which only produces gametes, the number of chromosomes in cells after meosis is half compared to the original cell.
What is mitosis?
The cell division which is for growth and repair of an organism.
Where are chromosomes found?
In the nucleus in most of the cells of your body.
