Unit 5 Heredity

What are the phases of meiosis I?

Prophase I, Metaphase I, Anaphase I, Telophase I

What is the role of meiosis I?

Form 2 daughter cells and introduces genetic variation

What are the phases of meiosis II?

Prophase II, Metaphase II, Anaphase II, Telophase II

What is the role of meiosis II?

form 4 haploid cells

Identify three differences between meiosis I and meiosis II,

Crossing over occurs in prophase 1, homologous chromosomes separate in meiosis 1, chromatids separate in meiosis 2

Identify what part of meiosis results in the reduction of chromosome number.

Anaphase 2 and telophase 2

Describe the daughter cells resulting from mitosis.

Identical DNA to parent cell

Describe the daughter cells resulting from meiosis.

Haploid cell with variation

When do homologous chromosomes separate during meiosis?

Anaphase 1

How do daughter cells receive both maternal and paternal chromosomes?

fertilization from sexual reproduction

How do homologous chromosomes separate during anaphase?

Spindle fibers attach to centromers of tetrad

What process occurs during meiosis I that causes daughter cells to be haploid?

2nd division

How does crossing over increase genetic diversity?

Introduces genetic variation

What is crossing over?

When chromosomes exchange genetic information.

What is independent assortment?

When chromosomes align during metaphase 1 and 2

What is random fertilization?

Random fusion of 1 egg and 1 sperm

How does independent assortment increase genetic diversity?

Introduces genetic variation

How does random fertilization increase genetic diversity?

Introduces variation, offspring have contribution from parents plus variation from meiosis in gamete formation

What substances are the carriers of genetic information?

DNA and RNA

How do ribosomes demonstrate common ancestry?

A common feature found in all life forms

What organisms have ribosomes?

All

How does a shared genetic code demonstrate common ancestry?

Relates organisms molecularly

What metabolic process do all organisms undergo which demonstrates common ancestry?

Glycolysis

What is the law of independent assortment?

genes for different traits can segregate independently from each other, genes can't be linked on the same chromosome

What is the law of segregation?

two alleles for a single trait will separate randomly, 50:50 chance of getting each gamete

What is the expected ratio of a monohybrid cross based on Mendel's laws

A test cross with heterozygotes should be 1:1

What is the expected ratio of a dihybrid cross based on Mendel's laws

9:3:3:1

What is complete dominance?

one allele is completely dominant over the other

What is codominance?

Equal expression of more than 1 allele

What is incomplete dominance?

A phenotypic blending of traits

How are the phenotypic and genotypic ratios of a monohybrid cross different in these different levels of dominance?

They aren't the same, depends on the nature of the allele

What are linked genes?

Genes that are on the same chromosome

How are the predicted ratios different in linked genes?

They can't be independently assorted

If the recombination frequency is 15%, how far apart are the two genes?

15 map units

What is a polygenic trait?

Trait controlled by more than one gene

What organelles contain DNA?

Nucleus, mitochondria, and chloroplasts

How does mitochondria, and chloroplasts containing DNA support the endosymbiotic theory?

Mitochondria and chloroplasts have double membranes

If a trait is found on the DNA in a chloroplast, what is the mode of inheritance?

Maternal

If a trait is mitochondrially linked, what is the mode of inheritance?

Maternal

What would you look for in a pedigree to identify if the trait is dominant or recessive?

If it's dominant, at least 1 parent will have the trait

What would you look for in a pedigree to identify if the trait is autosomal or sex-linked?

How common it is for males to have the recessive condition

What would you look for in a pedigree to identify if the trait is due to non-nuclear inheritance?

Look for unequal inheritence. Autosomal traits can be passed down by males and females equally, but only females can pass down mitochondrial inheritance

What is phenotype plasticity?

The ability of an organism to change phenotype due to environmental cues

What occurs during segregation in meiosis?

The migration of chromosomes to opposite poles

What phase does segregation in meiosis take place in?

Anaphase 1 and 2

What occurs during independent assortment in meiosis?

Homologous chromosomes or chromatids line p in a random way

What phase does independent assortment in meiosis take place in?

Metaphase 1 and 2

How does segregation lead to genetic variation?

Produces a combination of alleles different from others

What is fertilization?

fusion of egg and sperm

How does independent assortment lead to genetic variation?

Produced a variation in combination of alleles

What is the chromosomal basis of inheritance?

Inherited genes are because you inherited chromosomes from parents

How does fertilization lead to genetic variation?

A random egg and sperm makes a new combination of DNA

What is nondisjunction?

When homologous chromosomes don't seperate