Chapter 3- Genetics & Heredity Flashcards
What is a genotype?
genetic endowment inherited from ancestors
What is a phenotype?
observable, measurable characteristics
What was one early notions of heredity?
-Traits inherited from fathers
- 17th century – Anton van Leeuwenhoek
What does preformationism mean?
Sperm contains a tiny, preformed homunculus (little human/miniature version of themselves), in which creates a baby
What did Caspar Wolff (1759) believe?
Sperm and ovum unite to create a single cell
What did the ‘father of modern genetics’ Gregor Mendel believe about inherited characteristics and gametes?
- Inherited characteristics produced by BLANK
- transmitted BLANK from generation to generation
- Each characteristic determined by pair of BLANK
- one BLANK from each parent
- Members of gene pair may BLANK in their effects
- one may BLANK the other
- When gametes produced:
- gene pair for each attribute BLANK
- each gamete contains only one member of each BLANK of BLANK
- Inherited characteristics produced by genes
- transmitted unchanged from generation to generation
- Each characteristic determined by pair of genes
- one inherited from each parent
- Members of gene pair may differ in their effects
- one may dominate the other
- When gametes produced:
- gene pair for each attribute divides
- each gamete contains only one member of each pair of genes
What are the current notions about chromosomes?
2pts
- normal human cells contain 2 sets of 23 chromosomes (23-pair)
- 1 member of each pair from mother, 1 from father
What are the current notions about gametes?
2pts
- cells that are involved in reproduction
- contain only 23 individual chromosomes (1/2 of each of the 23 pairs)
What is meiosis in regards to gametes and the 23 chromosomes?
3pts
- gamete formation
- each of the 23 pairs split
- result is two “child” cells containing 23 individual chromosomes
Exchange of equivalent genetic material between homologous chromosomes at points where they cross-over during lining up.
What process am i?
crossing over in meiosis
What is meiosis in simple terms?
A process where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells – sperm in males, eggs in females
How are sex chromosomes determined, what are autosomes?
6pts
- Autosomes: 22 of the 23 pairs are found in both males and females
- the 23rd pair determines sex
- X- longer of the two
- y - shorter
- Females- 23rd pair- both X’s (XX)
- Males- 23rd pair one X and one Y (XY)
What is the androsperm vs Gynosperm ?
4 pts each.
Androsperm:
- Y- carrying sperm
- Lighter, swim faster, short lived
Gynosperm:
- X-carrying sperm
- heavier, swim more slowly, longer-lived
Alternative forms of a gene coded for a particular trait.
What am I?
Alleles
If both alleles are the same, child is BLANK with respect to that trait.
What am I?
Homozygous
If alleles are different, then BLANK for the that trait.
What am I?
Heterozygous
Genotype lead to the phenotype/ the phenotype is determined by its genotype.
True or false
True
Autosomal Genetic Abnormalities
Tay Sachs disease is an example of what type of abnormality?
Recessive abnormality
Autosomal Genetic Abnormalities
Cystic fibrosis is an example of what type of abnormality?
Recessive abnormality
Autosomal Genetic Abnormalities
Phenylketonuria (PKU) is an example of what type of abnormality?
What is PKU in simple terms
Recessive abnormality
-cannot metabolize phenylalanine, build up of pyruvic acid
Autosomal Genetic Abnormalities
What is one dominant abnormality?
Huntington’s disease
What are two sex-linked characteristics ?
- recessive genes
- located on X chromosome
What are 4 sex-linked disorders?
- Red-Green colour blindness
- Hemophilia
- Duchenne’s muscular dystrophy
- Fragile- X syndrome
What is an example of a chromosomal abnormality (1pt), its characteristics (5pts) and a possible reason why it can occur (1pt)?
Down syndrome
- Trisomy 21: an extra copy of a chromosome
Characteristics:
- intellectual impairment, eye, ear, heart, and tongue defects
-incidence related to mother’s age
What are 3 disorders of the sex chromosomes?
3pts
- Turner’s syndrome: X0- girls who have when one of the X chromosomes missing or partially missing
- Klinefelter’s syndrome: XXY- boys born with extra female chromosome (X)
- Poly-Y syndrome: XYY- extra copy of y chromosome
Heritability of psychological characteristics
What are the two methods of assessing heritability?
2pts for each.
Selective Breeding:
- Robert Tryon
- Cross-fostering
Family studies:
- Pedigree studies
- Kinship (consanguinity studies)
