NOTES : Chapter 6.1 – Chromosomes and Meiosis

• Chromosome _____________ must be maintained in animals.

• Many plants have more than ________________ of each chromosome.

• _____________ and _____________ are types of nuclear division that make different types of cells.

• Mitosis makes more _______________ cells.

• Meiosis makes ___________ cells from ____________ cells.

- Meiosis occurs in _______________.- Meiosis produces __________________.

KEY CONCEPTGametes have ______________ of chromosomes that body cells have.

• Body cells are also called __________ cells.

• _______ cells develop into gametes.

– Germ cells are located in the __________ and ___________.

– Gametes are sex cells: __________ and ______________.

– Gametes have ________ that can be passed to offspring.

• Your body cells have _____ pairs of chromosomes.

– ____________ pairs of chromosomes have the same structure.

– For each _______________ pair, one chromosome comes from each__________.

• Chromosome pairs 1-22 are ________________.

• ___________________, ___ and ____, determine gender in mammals.

• Fertilization between egg and sperm occurs in ________________________.

• ______________ (____) cells have _____ copies of every chromosome.

– ________ cells are diploid.

– _________ the chromosomes come from each _____________.

• ____________(___) cells have ______ copy of every chromosome.

– _____________ are haploid.

– Gametes have ________________ and ____________________.

Chpater 6.2 – Process of MeiosisKEY CONCEPTDuring meiosis, diploid cells undergo______ cell divisions that result in ___________ cells.

Cells go through two rounds of division in meiosis.Meiosis ______________________ number and creates _____________ diversity.

Meiosis I and meiosis II each have _________________, similar to those in _________________.

– Pairs of ________________ chromosomes __________________ in meiosis I.

– Homologous chromosomes are similar but _______________________.

– _________________chromatids ________________ in meiosis II.

– Sister chromatids are ________________ of the _____________ chromosome.

• Meiosis I occurs after _______ has been ________________.

• Meiosis I divides homologous chromosomes in four phases.

• Meiosis II divides ____________ chromosomes in four phases.

• __________ is _________ replicated between meiosis I and meiosis II.

• Meiosis differs from mitosis in significant ways.

- Meiosis has _______________________________ while mitosis has __________.- In mitosis, homologous chromosomes __________________________.- Meiosis results in ________________ cells; mitosis results in ________________ cells.

• Gametogenesis is the production of _________________.

• Gametogenesis differs between females and males.

• _____________ become motile.

• Sperm primarily contribute ____________ to an embryo.

• Eggs contribute _____________, __________________, and ________________ to an embryo.

• During meiosis, the egg gets most of the contents; the other cells form ___________________.

Note 6.3 - Mendel and Heredity

• _________________ are distinguishing characteristics that are _____________________.

• __________________ is the study of biological inheritance patterns and variation.

KEY CONCEPTMendel’s research showed that traits are inherited as discrete units.

• _______________________ showed that traits are inherited as discrete units.

• Many in Mendel’s day thought traits were _________________.

• Mendel made three key decisions in his experiments.

– use of _________________ plants

– control over ____________________

– observation of seven “either-or” traits

– Mendel used ______________ to fertilize selected pea plants.

– _____ generation crossed to produce ___________ generation

– interrupted the self-pollination process by removing ________________________

– Mendel allowed the resulting plants to _____________________.

– Among the F1 generation, all plants had _____________ flowers

– F1 plants are all _________________ ( ________________________)

– Among the ___ generation, some plants had __________ flowers and some had _________

– Mendel drew three important conclusions.

– Traits are inherited as discrete units.

– Organisms inherit _________________ of each gene, one from each __________.

– The two copies ______________ ( _______________) during gamete formation.

– The last two conclusions are called the ______________________________.

Notes 6.4 - Traits, Genes, AllelesKEY CONCEPTGenes encode ____________________ that produce a diverse range of traits.

• The same gene can have many versions.- A __________ is a piece of DNA that directs a cell to make a certain ______________.- Each gene has a _______________, a specific position on a pair of homologous chromosomes.

• An _________________ is any _________________ form of a gene occurring at a specific ___________ on a chromosome.

• Each parent donates one ____________ for every _________.

• ____________________ describes two alleles that are the __________ at a specific locus.

• _____________________describes two alleles that are______________ at a specific locus.

• All of an organism’s genetic material is called the _____________.

• A _________________ refers to the makeup of a specific set of genes.

• A ________________________ is the physical expression of a trait.

Alleles can be represented using _______________.

A _________________ allele is expressed as a phenotype when at least one allele is dominant. A__________________ allele is expressed as a phenotype only when two copies are present. Dominant alleles are represented by ____________ letters; recessive alleles by ________________ letters.

• Both homozygous dominant and heterozygous genotypes yield a dominant phenotype.

• Most traits occur in a range and do not follow simple dominant-recessive patterns.

Notes 6.5 - Traits and Probability

KEY CONCEPTThe inheritance of traits follows the rules of probability.

• The _______________________ is a grid system for predicting all possible _________________ resultingfrom a cross.

– The axes represent the possible gametes of each parent.

– The boxes show the possible genotypes of the offspring.

The Punnett square yields the ____________ of possible _______________ and _______________.

A ____________________ cross involves one trait.

A __________________ is a cross between an organism with an unknown genotype and an organism withthe ______________________ phenotype.

A ___________________ cross involves two traits.Mendel’s dihybrid crosses with ________________________ plants yielded a _______________phenotypic ratio.

• Mendel’s dihybrid crosses led to his second law, the law of __________________________.

• The law of _____________________________________ states that allele pairs separate ______________________ of each other during meiosis.

• _____________________________ is the likelihood that something will happen.

• _____________________________ predicts an average number of _____________________, not an exactnumber of occurrences.

Notes 6.6 - Meiosis and Genetic Variation

KEY CONCEPT_________________________________ and ___________________________ during meiosis result ingenetic diversity.

• ______________________reproduction creates unique combination of genes.

– independent assortment of chromosomes in meiosis

– random fertilization of gametes

• Unique _________________________ may give a reproductive advantage to some organisms.

• _____________________________ during meiosis increases genetic diversity.

• Crossing over is the exchange of ________________________________ between_______________________ chromosomes.

– occurs during ______________________ of meiosis I

– results in _______________________________ of genes

– The farther apart two genes are located on a chromosome, the more likely they are to be separatedby crossing over.

– Genes located close together on a chromosome tend to be ___________________________, whichis called ______________________________.

• ________________________________ allows the distance between two genes to be calculated.

Chapter 7 Notes (7.1 - Chromosomes an Phenotypes)

KEY CONCEPTThe chromosomes on which genes are located can affect the expression of traits.

Two copies of each _____________________ gene affect phenotype.

• Mendel’s rules of inheritance apply to autosomal genetic disorders.

• A heterozygote for a recessive disorder is a ________________(Cc).

• Disorders caused by dominant alleles are uncommon. (Achondroplasia)

(dominant)

• Genes on sex chromosomes are called ____________________ genes.

– Y chromosome genes in mammals are responsible for __________ characteristics.

– X chromosome genes in mammals affect __________ traits. So most sex- linked traits are found on the ______-chromosome.

• Male mammals have an __________ genotype.

• All of a male’s __________________________ (those on X-chromosome) are expressed.

• Males have no ___________________ of sex-linked genes, so the X-chromosome traits will bedisplayed. X b Y = only “b” Example: __________________________

• Females have ________ genes, while males have only ________

• Female mammals have an __________ genotype.

• Expression of sex-linked genes is similar to _________________ genes in females. X B X b - Bb

• X chromosome ______________________ randomly “turns off” one X chromosome.

Chapter 7 Notes (7.2 - Complex Patterns of Inheritance)Phenotype can depend on interactions of alleles.

• In ________________________________, neither allele is completely dominant nor completelyrecessive.

– Heterozygous phenotype ________ is ___________________ between the two homozygous phenotypes____________

– Homozygous parental phenotypes not seen in ______________________

_________________________ alleles will both be completely expressed.

– _____________________________ alleles are neither dominant nor recessive.

– The ABO blood types result from _______________________ alleles.

– Many genes have more than _______ alleles.

• _________________________________ are produced by two or more genes.

The _____________________ interacts with genotype.

• Phenotype is a combination of _________________ and ______________________.

• The sex of sea turtles depends on both genes and the environment

Chapter 7 Notes (7.3 - Gene Linkage and Mapping)KEY CONCEPTGenes can be ___________________ to specific _______________________ on chromosomes.

• The _________________________ two genes are, the more likely they will be inherited together.

• _______________________________ frequencies are related to ___________________ between genes.

• ___________________________ show the relative locations of genes.

Chapter 7 Notes (7.4 - Human Genetics and Pedigrees)KEY CONCEPTA combination of methods is used to study human genetics.

Females can _________________ sex-linked genetic disorders, but not _________________ them.

• _____________________________ express all of their sex linked genes.

• Expression of the disorder depends on which parent ____________ the allele and the __________ of thechild.

A ______________________________ is a chart for tracing genes in a family.

• ____________________________ are used to infer genotypes on a pedigree.

• If the phenotype is more common in males, the gene is likely ____________________________.

A ________________is a picture taken during __________________________of all chromosomes in a cell.

• ____________________ can show changes in chromosomes.

• ___________________ of part of a chromosome or ____________ of a chromosome

• __________________________ in chromosomes

• ____________________________ or ___________________________ of part of a chromosome