Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
Concept of Blending Inheritance |
Parents of contrasting appearance produce offspring of intermediate appearance. |
|
Particulate theory of Inheritance |
Inheritance involves reshuffling of genes from generation to generation. |
|
Why use the garden pea (5) |
1. Easy to cultivate 2. Short generation 3. Normally self-pollinating, can be crossed by hand 4. True-breeding varieties available 5. Simple, objective traits |
|
Homozygous |
True-breeding |
|
Monohybrid Cross |
Varieties differing in only one trait |
|
Law of Segregation |
1. Each individual has a pair of factors for each trait. 2. The alleles separate during gamete formation. 3. Gametes contain one factor. 4. Fertilisation give offspring two factors. |
|
Gene locus |
Location of allele on chromosome. |
|
Heterozygous |
Different Alleles |
|
Genotype |
Two alleles an individual has fo one trait. |
|
Phenotype |
Physical appearance |
|
Allele |
Gene for specific trait |
|
Homologous |
Pair of chromosomes with same trait at same locus. |
|
Law of Independant Assortment |
Pair of factors for one trait separate independantly of factors for other traits All possible combinations can occur. |
|
Dihybrid Cross |
True-breeding plant differing in one trait |
|
Mendel tracked a trait... |
Start with true-breeding differing in two traits.\F1 shows both dominant characteristics. F1 self-pollinates. Observe. |
|
Testcross |
Determines genotype of individual with dominant phenotype. |
|
Genetic Disorders |
Medical conditions caused by alleles inherited from parents. |
|
Autosome |
Any chromosome other than sex chromosomes X & Y |
|
Autosomal Dominant |
Aa yes AA yes aa no |
|
Autosomal Recessive |
AA no Aa no aa yes |
|
Methemoglobinema |
AUTOSOMAL RECESSIVE Chromosome 22 Accumulates methemoglobin in blood, hands look blue |
|
Cystic Fibrosis |
AUTOSOMAL RECESSIVE Chromosome 7 Mucus in bronchial tubes and pancreatic ducts. Affected Ca+ channels |
|
Phenylketonuria |
AUTOSOMAL RECESSIVE Affects nervous system development Lacks enzyme for normal metabolism of phenylalanine - diet low in that enzyme. |
|
Phenylketonuria diet low in |
Milk Dairy Fish Eggs Chicken Eggs Beans Nuts |
|
Osteogenesis Imperfecta |
AUTOSOMAL DOMINANT Weak, brittle bones Mutation in genes required for synthesis of type 1 collagen |
|
Huntington Disease |
AUTOSOMAL DOMINANT Chromosome 4 Mutated gene coding for protein huntingtin Progressive degeneration of brain cells causing large clumps inside neurons Problems appear in middle age normally |
|
Hereditary Spherocytosis |
AUTOSOMAL DOMINANT Minowski-Chauffard Syndrome Chromosome 8, ankyrin-1 gene Red blood cells spherical, fragile, burst |
|
Co-dominance |
More than one allele is fully expressed, eg ABO blood groups. |
|
Incomplete Dominance |
Heterozygote has phenotype intermediate between that of either homozygote. Eg red, white, pink flowers. |
|
Familial Hypercholesterolemia |
INCOMPLETE DOMINANCE Homozygotes develop fatty deposits in skin & tendons; childhood heart attacks. Heterozygotes may get heart attacks in early adulthood. |
|
Incomplete Penetrance |
The dominant allele may not always lead to the dominant phenotype in a heterozygote. Exhibit varying degrees of penetrance. |
|
Polydactyly |
INCOMPLETE PENETRANCE Extra digits on hands or feet or both. Not all individuals who inherit the dominant polydactyly will exhibit the trait. |
|
Pleiotropy |
A single mutant gene affects two or more distinct and seemingly unrelated traits. |
|
Marfan Syndrome |
PLEIOTROPY Chromosome 15 Abnormal connective tissue (disproportionate hands, legs, feet etc., weak aorta, poor eyesight. |
|
Pleiotropy Examples |
Porphyria Sickle Cell Aneamia |
|
Polygenic Inheritance |
A trait is governed by two or more genes having different alleles. Additive effects. |
|
Polygenic Inheritance examples |
Skin colour, height, hair colour |
|
X-linked Inheritance |
Nothing to do with gender. X chromosome carries genes. Y chromosome ONLY codes for being male. |
|
X linked Inheritance Discoveries |
Colubia University in 1900s, headed by Thomas Hunt Morgan on fruit flies (easy, inexpensive, similar sex chromosome pattern as humans) |
|
Colour Blindness |
X LINKED RECESSIVE Allele for blue-sensitive is autosomal. Green and red-sensitive cells are X linked. |
|
Menkes Syndrome |
X LINKED RECESSIVE Defective allele on X. Disrupts movement of Cu in and out of cell. Kinky hair, poor muscle tone, siezures, low body temp. |
|
Muscular Dystrophy |
X LINKED RECESSIVE Wasting away of muscle. Caused by absence of protein dystrophin. |
|
Adrenoleukodystrophy |
X LINKED RECESSIVE Failure of carrier protein to move an enzyme or long fatty acid into peroxisomes. |
|
Haemophilia |
X LINKED RECESSIVE Absence or minimal clotting factor VIII or IX. Affected person's blood doesn't clot or clots slowly. |