Heredity, Meiosis, and Genetic Variation: Comprehensive Biology Review

What are somatic cells?

Body cells that are diploid, containing 46 chromosomes.

What are gametes?

Sex cells made through meiosis.

What is the main difference between sexual and asexual reproduction?

Sexual reproduction involves two different cells, while asexual reproduction involves the division of a single cell to produce identical cells.

What is cloning?

A form of asexual reproduction that involves creating a genetically identical copy of an organism.

What is a karyotype?

A picture of chromosomes used to examine chromosomal disorders.

What is nondisjunction?

An error in meiosis where chromosomes do not separate evenly, leading to gametes with an abnormal number of chromosomes.

What is Trisomy 21?

Also known as Down Syndrome, it is the most common chromosomal disorder characterized by three copies of chromosome 21.

What is Klinefelter syndrome?

A chromosomal disorder in males characterized by an extra X chromosome (XXY), leading to undeveloped testes and other physical traits.

What is Turner syndrome?

A condition in females caused by the absence of one X chromosome (XO), leading to short stature and underdeveloped ovaries.

What is Mendel's Law of Segregation?

Each individual has two factors for each trait, which segregate during gamete formation, resulting in each gamete containing only one factor from each pair.

What is a dihybrid cross?

A genetic cross examining two traits simultaneously.

What is incomplete dominance?

A genetic situation where a heterozygote has an intermediate phenotype between that of either homozygote.

What is codominance?

A genetic scenario where both alleles are expressed equally in the phenotype of the offspring.

What is polygenic inheritance?

A trait controlled by two or more sets of alleles, each contributing to the phenotype.

What is pleiotropy?

A situation where one gene affects multiple characteristics of an individual.

What is epistasis?

A phenomenon where a gene at one locus interferes with the expression of a gene at a different locus.

What is the role of mitochondria in inheritance?

Mitochondrial DNA is maternally inherited and does not follow Mendelian inheritance patterns.

What is the significance of Punnett squares?

They are used to predict the genotypes and phenotypes of offspring based on parental alleles.

What happens during prophase I of meiosis?

Homologous chromosomes pair and exchange segments through a process called crossing over.

What is the outcome of meiosis II?

Meiosis II results in the separation of sister chromatids, producing four haploid cells.

What are the characteristics of autosomal recessive disorders?

They require two copies of the recessive allele for the disorder to be expressed and can be passed down through carriers.

What is the difference between homologous chromosomes and sister chromatids?

Homologous chromosomes carry the same information but may not be identical, while sister chromatids are identical copies of a chromosome.

What is binary fission?

A form of asexual reproduction where a single cell divides into two identical daughter cells.

What is parthenogenesis?

A form of asexual reproduction where an egg develops into an organism without fertilization.

What is the role of chiasmata in meiosis?

Chiasmata are the points where homologous chromosomes exchange genetic material during prophase I.

What is the significance of genetic variation?

Genetic variation is essential for the survival and adaptability of species.

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 primary purpose of meiosis?

To produce haploid gametes in sexually reproducing diploid organisms.

What does diploid mean?

A cell containing two full sets of chromosomes, represented by 2n.

What are haploid cells?

Cells that contain one set of chromosomes, represented by n, such as gametes.

How many daughter cells does meiosis produce?

Four haploid daughter cells.

What is crossing over and when does it occur?

Crossing over is the exchange of genetic material between nonsister chromatids during prophase I of meiosis I.

How does crossing over increase genetic diversity?

It results in recombinant chromatids, which increases variation among gametes.

What is random assortment of chromosomes?

The random distribution of homologous chromosomes during metaphase I, affecting which chromosomes end up in each gamete.

How does fertilization contribute to genetic diversity?

It combines genetic information from two parents, resulting in varied offspring.

What is the difference between mitosis and meiosis in terms of genetic content?

Mitosis produces two genetically identical daughter cells, while meiosis produces four genetically varied haploid cells.

What happens during prophase I of meiosis I?

The nuclear envelope disappears, DNA coils into visible chromosomes, and homologous chromosomes pair up.

What occurs during anaphase I of meiosis I?

Fibers separate chromosome pairs, migrating each double chromosome to opposite sides of the cell.

What is the outcome of telophase I in meiosis?

The nuclear envelope reappears, forming two nuclei, each with one double chromosome from each pair.

What is the role of cytokinesis in meiosis?

It separates the cell into two daughter cells, which are haploid and genetically different.

What happens during prophase II of meiosis II?

The nuclear envelope begins to disappear again and spindle fibers form.

How can nondisjunction contribute to genetic disorders?

It can result in gametes with an abnormal number of chromosomes, leading to disorders in offspring.

What is the law of segregation?

The principle that alleles segregate from each other during gamete formation.

How does independent assortment contribute to genetic variation?

It allows for different combinations of alleles to be passed to gametes during meiosis.

What is an example of a genetic disorder caused by chromosomal inheritance?

Huntington's disease, caused by a single defective gene on Chromosome 4.

What visual representation can be used to analyze chromosomal inheritance?

Pedigrees can be used to predict the inheritance of traits and disorders.

What is the significance of the number of chromosomes in gametes?

Haploid gametes ensure that offspring have the correct diploid number when fertilization occurs.

What is the difference in the number of cell divisions between mitosis and meiosis?

Mitosis involves one division, while meiosis involves two rounds of division (meiosis I and II).

What happens to chromosomes during telophase II?

The nuclear envelope reappears, and chromosomes begin to uncoil, leading to the formation of four haploid cells.

What is the result of meiosis II?

It separates double chromosomes into single chromosomes, resulting in four genetically varied haploid daughter cells.

What is the role of spindle fibers in meiosis?

They help align and separate chromosomes during the different phases of meiosis.

What is the genetic composition of the daughter cells produced by meiosis?

Four haploid daughter cells that are genetically different from each other and the parent cell.

How does meiosis contribute to evolution?

By generating genetic diversity, which is essential for natural selection and adaptation.

What does independent assortment refer to?

Independent assortment suggests that genes for two or more traits are sorted into gametes independently, meaning genes are not linked.

How does random fertilization contribute to genetic variation?

Random fertilization allows any genetically unique sperm to join any genetically unique egg, producing offspring with unique combinations of chromosomes.

What is a monohybrid cross?

A monohybrid cross examines the inheritance of one trait.

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

It states that alleles for separate traits can be packaged in every possible combination into gametes, allowing for genetic diversity.

What is a pedigree?

A pedigree is a visual representation tracing the history of a trait through familial generations, helping to identify inheritance patterns.

What are dominant and recessive alleles?

A dominant allele is expressed in the phenotype if inherited, while a recessive allele is expressed only when the dominant allele is not present.

What is the genotype?

The genotype is the combination of inherited alleles, typically represented by two letters.

What is the phenotype?

The phenotype is the physical expression or result of the genotype.

How do mutations contribute to genetic diversity?

Mutations can introduce variations in alleles, contributing to genetic diversity in offspring.

What is the role of nucleic acids in heredity?

Nucleic acids (DNA and RNA) carry genetic information and are essential for the continuity of life.

What is the purpose of using Punnett squares?

Punnett squares are used to illustrate the probable outcomes of genetic crosses.

What is the probability rule for 'A OR B' events?

To determine the probability of A OR B happening, you add the probability of A to the probability of B.

What is the probability rule for 'A AND B' events?

To determine the probability of A AND B happening, you multiply the probability of A by the probability of B.

What is the impact of inherited mutated alleles?

Inherited mutated alleles can lead to genetic disorders and affect the functioning of the offspring.

What are core metabolic pathways?

Core metabolic pathways, such as cellular respiration and glycolysis, are conserved across all domains of life and support the concept of common ancestry.

What is the significance of shared genetic processes?

Shared genetic processes support the concept of common ancestry by linking organisms through fundamental features.

How do scientists use hypothesis testing?

Scientists use hypothesis testing to validate or invalidate predictions based on observations and data.

What is the purpose of a chi-square goodness-of-fit test?

The chi-square goodness-of-fit test assesses how well observed data fit with expected data based on a specific hypothesis.

What is the relationship between alleles and gametes?

The segregation of parental alleles into gametes provides opportunities for varied combinations during fertilization.

What does it mean for a trait to be autosomal dominant?

An autosomal dominant trait shows a pattern of affected offspring having affected parents.

What does it mean for a trait to be autosomal recessive?

An autosomal recessive trait shows a pattern of affected offspring having unaffected parents.

What is the importance of conserved processes in biology?

Conserved processes in biology provide evidence for the continuity of life and common ancestry among all organisms.

What are homologous chromosomes?

Homologous chromosomes are pairs of chromosomes that carry alleles for the same trait.

What do Mendel's laws describe?

The inheritance of genes and traits on different chromosomes.

What is a gene?

A unit of heredity coding for a trait.

What is a trait?

A genetically determined characteristic of an organism.

What is an allele?

A specific variation of a gene.

How are alleles inherited?

Organisms inherit alleles from both parents and can inherit different alleles for the same gene.

What is the difference between a dominant allele and a recessive allele?

A dominant allele is always expressed in the phenotype if inherited, while a recessive allele is only expressed when the dominant allele is not present.

What is a genotype?

The combination of inherited alleles, typically represented by two letters.

What is a phenotype?

The physical result or expression of the genotype.

What does Mendel's law of segregation state?

Alleles are segregated into separate gametes during meiosis.

What is Mendel's law of independent assortment?

Two or more genes assort independently of each other, allowing for genetic variation.

What is a Punnett square used for?

To illustrate the probable outcomes of a genetic cross.

What does a pedigree help identify?

Types of inheritance such as autosomal dominant and autosomal recessive.

What is hypothesis testing?

A method used by scientists to reject or fail to reject statistical hypotheses.

What is a null hypothesis?

It states there is no relationship or difference between two groups of data.

What is an alternative hypothesis?

It states that observed results are due to a nonrandom cause.

What is the purpose of a chi-square test?

To determine if there is a significant relationship between two groups of data.

What is the first step in performing a chi-square goodness-of-fit test?

Establish a research question.

What do you compare in a chi-square test?

Observed outcomes are compared to expected outcomes.

What do you do if the chi-square value is greater than the critical value?

Reject the null hypothesis.

What do you do if the chi-square value is less than the critical value?

Fail to reject the null hypothesis.

What is the significance of map distance in linked genes?

It indicates the relative distance between genes on a chromosome.

What are sex-linked traits?

Traits that are associated with genes located on sex chromosomes.

How do sex-linked traits differ from Mendelian traits?

Sex-linked traits are influenced by the sex of the individual, while Mendelian traits follow simple inheritance patterns.

What are linked genes?

Genes that are adjacent and close to one another on the same chromosome, inherited together.