Heredity AP Biology Exam Review

Flashcards about heredity, meiosis and genetic diversity

Label the parts of the chromosome.

1) sister chromatid 2) short arm or p arm 3) centromere 4) long arm or q arm

Where does meiosis take place? What does the process of meiosis create?

Meiosis takes place in reproductive organs in sexual organisms. Meiosis (gametogenesis) creates gametes (sex cells) such as eggs and sperm.

What are the names of the steps of meiosis?

Prophase I, Metaphase I, Anaphase I, Telophase I, Cytokinesis, Prophase II, Metaphase II, Anaphase II, Telophase II, Cytokinesis

Mitosis produces what types of cells, how many cells are made, and are the ending cells haploid or diploid?

Mitosis produces somatic (body) cells, makes 2 genetically identical cells, and the ending cells are diploid.

Meiosis produces what types of cells, how many cells are made, and are the ending cells haploid or diploid?

Meiosis produces gamete (sex) cells (egg and sperm), makes 4 genetically different cells, and the ending cells are haploid.

What is crossing over? When does it occur? Why is it important for genetic variation?

Crossing over occurs during prophase I and is the genetic exchange of information between homologous chromosomes. It is important for genetic variation because the exchange of genetic material causes the genes to be recombined creating a new variation.

What is fertilization? How does this lead to genetic variation?

Fertilization is the process of a sperm entering an egg.

Describe Mendel’s law of segregation.

Allele pairs separate or segregate during gamete formation and randomly unite at fertilization.

Describe Mendel’s law of independent assortment.

States that the alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.

What is the purpose of a Punnett Square?

Used to determine the statistical likelihood of each possible genotype of the offspring of two parents for a given trait or traits

Compare dominant to recessive alleles.

Dominant alleles will always be seen in the phenotype if present. While recessive alleles will be masked by the dominant allele if heterozygous and will only be visible in the phenotype if there are two recessive alleles.

Compare homozygous dominant (HD), heterozygous (HE), and homozygous recessive (HR).

HD = two dominant alleles: Ex: AA will express the dominant phenotype, HE = one dominant allele and one recessive allele: Ex: Aa will express the dominant allele, HR = two recessive alleles, Ex: aa, will express the recessive phenotype.

When is the product rule used?

The product rule is used when looking at an AND situation. What is the probability that X and Y will occur?

When is the summation rule used?

Summation rule is used during an OR situation. What is the probability that X OR Y will occur?

What is codominance?

Both phenotypes are visible in the heterozygous individuals.

What is incomplete dominance?

The phenotypes are blended together like paint for the heterozygous individuals.

What are multiple alleles?

For many traits there can be multiple alleles in the population. But each individual only has TWO.

What are polygenic traits?

These are traits that are controlled by many different genes.

What is a linked gene?

When two genes are located on the same chromosome they are called linked genes because they tend to be inherited together.

Why don’t chloroplast and mitochondrial DNA follow Mendelian genetic rules?

Extranuclear genes present uniparental inheritance – all progeny, regardless of sex, have the phenotype of one parent.

In animals, where do the mitochondria come from?

Mitochondria comes from the mother.

What are the basic rules for constructing a pedigree?

Squares are males, circles are females, straight lines represent mating lines, vertical lines represent children

What is a pedigree used for?

A pedigree is used to trace a trait through a family's history.

What is phenotype plasticity?

Phenotypic plasticity is the ability of an organism to change in response to stimuli or inputs from the environment.

What is DNA Methylation?

DNA methylation is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription.

What is Histone Modification?

The modifications made to histones can alter gene expression because by altering chromatin structure.

What are some environmental factors that can influence your phenotype?

Environmental factors such as diet, temperature, oxygen levels, humidity, light cycles, and the presence of mutagens can all impact which of an animal's genes are expressed, which ultimately affects the animal's phenotype.