Bio 1220 Final

What is mitosis?

A process where a single parent cell divides to form two identical daughter cells.

How do daughter cells compare to the parent cell in mitosis?

The daughter cells are identical to each other and to the parent cell.

What is the primary function of mitosis in unicellular organisms?

To accomplish asexual reproduction.

What is the primary function of mitosis in multicellular organisms?

To facilitate growth and tissue repair.

What is meiosis?

A process where a single parent cell divides to produce four genetically diverse daughter cells.

How do daughter cells compare to the parent cell in meiosis?

The daughter cells are genetically different from each other and from the parent cell.

What are gametes?

Reproductive cells (sperm and eggs) produced through meiosis.

What is DNA?

The molecule that carries genetic information, located in the nucleus of cells.

What are genes?

Discrete segments of DNA that code for specific proteins and traits.

What are chromosomes?

Long strands of DNA that contain many genes.

How many chromosomes do human cells have?

46 chromosomes.

What is the cell cycle?

The sequence of stages that a cell goes through from division to division.

What are the phases of the cell cycle?

Interphase (G1, S, G2) and the Mitotic phase (Mitosis and Cytokinesis).

What occurs during the S phase of interphase?

DNA synthesis occurs, resulting in chromosomes consisting of sister chromatids.

What happens during prophase of mitosis?

Chromosomes coil tightly and become distinct; centrosomes move to opposite poles.

What is the metaphase plate?

The equatorial plane where chromosomes align during metaphase.

What occurs during anaphase of mitosis?

Sister chromatids are pulled apart toward opposite poles of the cell.

What happens during telophase of mitosis?

Chromosomes reach opposite poles, and new nuclear envelopes form around each set.

What is cytokinesis?

The division of the cytoplasm, resulting in two separate daughter cells.

What are homologous chromosomes?

Pairs of chromosomes that have the same genes but may have different alleles.

What is the difference between diploid and haploid cells?

Diploid cells have two sets of chromosomes (2n), while haploid cells have one set (n).

What is the role of crossing over in meiosis?

It increases genetic variation by exchanging segments between homologous chromosomes.

What is independent assortment?

The random distribution of homologous chromosomes during meiosis.

What is random fertilization?

The process by which any sperm can fertilize any egg, contributing to genetic diversity.

What is nondisjunction?

The failure of chromosomes to separate properly during meiosis, leading to abnormal chromosome numbers.

What is trisomy 21?

A genetic condition caused by an extra 21st chromosome, commonly known as Down syndrome.

What is a gene?

A hereditary unit that carries information coding for a specific trait.

What are alleles?

Different versions of a gene that can exist at a specific locus.

What is a homozygous organism?

An organism with two identical alleles for a trait.

What is a heterozygous organism?

An organism with two different alleles for a trait.

What is a phenotype?

The expressed physical traits of an organism.

What is a genotype?

The genetic makeup of an organism, represented by its alleles.

What did Gregor Mendel study?

The principles of inheritance using pea plants.

What is a monohybrid cross?

A genetic cross between individuals differing in one trait.

What is the P generation?

The parental generation in a genetic cross.

What is the F1 generation?

The first generation of offspring from a genetic cross.

What is the F2 generation?

The second generation of offspring from a genetic cross.

What is the significance of Mendel's experiments?

He established the foundational principles of genetics and inheritance.

What is the chromosomal basis of genetics?

The concept that genes are located on chromosomes, which occur in homologous pairs.

What occurs during meiosis regarding homologous chromosomes?

Homologous chromosomes and alleles separate.

What do gametes carry for each trait?

Only one allele for each trait.

What happens during fertilization of gametes?

Homologous chromosomes come together, and the zygote gains two alleles for each trait.

How many alleles does each parent contribute to their offspring?

One allele for each trait.

What is a Punnett square used for?

To predict the results of genetic crosses.

What is the phenotypic ratio of a monohybrid cross?

3 dominant : 1 recessive.

What is the genotypic ratio of a monohybrid cross?

1 homozygous dominant : 2 heterozygous : 1 homozygous recessive.

What are the possible offspring from a homozygous dominant male (WW) and a homozygous recessive female (ww)?

All offspring are heterozygous (Ww) with widow's peak.

What is the probability that two heterozygous parents (Ww × Ww) have four children, all with straight hairlines (ww)?

The probability is calculated based on the genotypic ratio.

What is the F1 generation in a genetic cross?

The first generation of offspring from the parental (P) generation.

What does 'alleles segregate' refer to?

The separation of alleles during gamete formation.

What is the significance of the P generation?

It is the parental generation used in genetic crosses.

What is the result of a monohybrid cross between two heterozygous individuals?

A phenotypic ratio of 3 dominant to 1 recessive.

In a Punnett square, what does each box represent?

A possible genotype of the offspring.

What is the outcome of a cross between two heterozygotes (Ww)?

The offspring can have widow's peak or straight hairline.

What does the term 'homozygous' mean?

Having two identical alleles for a trait.

What does the term 'heterozygous' mean?

Having two different alleles for a trait.

What is the role of gametes in fertilization?

Gametes unite to form a diploid zygote.

What does 'diploid' refer to?

A cell that contains two complete sets of chromosomes.

What does 'haploid' refer to?

A cell that contains one complete set of chromosomes.

What is the significance of paired alleles in a zygote?

They determine the genetic traits of the offspring.

What is a dihybrid cross?

A cross between individuals differing in two traits.

What traits did Mendel use in his dihybrid cross?

Round and yellow seeds (RRYY) with wrinkled and green seeds (rryy).

What phenotype did the F1 generation exhibit in Mendel's dihybrid cross?

Dominant round and yellow seeds.

What is the expected phenotypic ratio of a dihybrid cross?

9:3:3:1.

What does Mendel's law of segregation state?

Each pair of alleles segregates independently during gamete formation.

What is a testcross used for?

To determine the genotype of an individual displaying a dominant phenotype.

What is the purpose of pedigree analysis?

To analyze the inheritance of traits across generations.

What is the difference between recessive and dominant disorders?

Recessive disorders require a homozygous recessive genotype, while dominant disorders can occur in homozygous dominant or heterozygous individuals.

What is incomplete dominance?

A situation where heterozygotes exhibit a phenotype that is intermediate between the two homozygous phenotypes.

Provide an example of incomplete dominance.

Snapdragons with red (RR), white (rr), and pink (Rr) flowers.

What is codominance?

A situation where both alleles in a heterozygote are fully expressed.

Provide an example of codominance.

Certain horse breeds with red (RR) and white (rr) fur producing roan (Rr) fur.

What is polygenic inheritance?

A type of inheritance where multiple genes influence a single trait.

How does pleiotropy affect traits?

A single gene can affect multiple phenotypic traits.

What is gene linkage?

Genes that are located close together on the same chromosome and are inherited together.

What are the implications of gene linkage in inheritance patterns?

Linked genes do not assort independently and can lead to unexpected phenotypic ratios.

What is the expected outcome of a testcross involving a homozygous recessive individual?

It reveals the genotype of the unknown individual based on the phenotypes of the offspring.

What is the significance of Mendel's experiments with pea plants?

They established the foundational principles of inheritance and genetics.

What is the probability of obtaining a homozygous recessive offspring (rryy) from a dihybrid cross?

1/16.

How can recessive disorders persist in a population?

Heterozygous individuals can carry the allele without expressing the disorder.

What is the role of close relatives in the inheritance of recessive disorders?

They are more likely to share rare alleles, increasing the chance of offspring with genetic disorders.

What is the expected phenotypic ratio from a cross of two heterozygous individuals for a trait?

3:1 for a single trait.

What does the term 'carrier' refer to in genetics?

An individual who has one copy of a recessive allele but does not express the associated trait.

What is the relationship between genotype and phenotype?

Genotype refers to the genetic makeup, while phenotype refers to the observable traits.

What is the significance of Mendel's law of independent assortment?

It states that the inheritance of one trait does not affect the inheritance of another.

What is the expected genotypic ratio from a dihybrid cross?

1:2:1:2:4:2:1:2:1.

How does the chromosome theory of inheritance explain Mendel's laws?

It states that genes are located on chromosomes, which segregate and assort independently during meiosis.

What is produced by crossing over during meiosis?

Recombinant phenotypes.

What is the recombination frequency if there are 391 recombinants out of 2300 total offspring?

0.17 or 17%.

What are parental gametes in the context of genetics?

Gametes that are identical to the parents' genetic makeup.

What is the significance of gene linkage in genetics?

More recombinant phenotypes are produced between genes that are farther apart on a chromosome.

What is the structure of human somatic cells in terms of chromosomes?

44 autosomes and two sex chromosomes.

What are sex-linked genes?

Genes on the sex chromosomes that code for traits other than sex.

How do males inherit sex-linked traits?

Males receive all their sex-linked traits from their mothers.

What is the outcome for a male with a recessive allele on the X chromosome?

The recessive allele is always expressed.

What was the conclusion of the Hershey-Chase experiment?

DNA serves as the genetic material.

What are the two components of chromosomes?

DNA and proteins.

What is the basic structure of a DNA nucleotide?

A sugar, a phosphate group, and a nitrogenous base.

What are the nitrogenous bases found in DNA?

Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).

What is the role of DNA helicase in DNA replication?

It unzips the parent DNA molecule by breaking hydrogen bonds.