unit 6 bio test.

Number of Parent Cells in Mitosis

Number of Parent Cells in Mitosis

1

Number of Parent Cells in Meiosis

1

Parent Cells in Mitosis

Diploid

Parent Cells in Meiosis

Diploid

Type of Cells in Mitosis

Somatic (Body Cells)

Type of Cells in Meiosis

Gametes (Sex cells, egg, sperm)

Number of Daughter Cells in Mitosis

2

Number of Daughter Cells in Meiosis

4

Daughter Cells in Mitosis

Diploid

Daughter Cells in Meiosis

Haploid

Purpose of Mitosis

Asexual reproduction for cell growth, repair and development by producing TWO identical daughter cells

Purpose of Meiosis

Sexual reproduction to produce gametes with half the chromosomes of the parent cell

Human chromosome number (Body Cell)

46

Human chromosome number (Gametes)

23

Male Gametes

Sperm

Female Gametes

Egg/Ovum

Fertilization

Joining of the egg and sperm

Why half the chromosomes?

So that fertilization can occur which restores the normal chromosome number in the offspring

Somatic/Body Cells are produced in 2 ways

Mitosis

Zygote through fertilization (First Body Cell)

Diploid (2n)

Normal chromosome number for an organism that is found in body or somatic cells (or in the zygote)

Haploid (n)

HALF the normal chromosome number, found ONLY in gametes or sex cells

23 individual chromosome (NO PAIRS)

Homologous chromsomes

Pairs (2n) of chromosomes with the same gene location

NOT IDENTICAL to each other (each is n)

Are similar: one from mother (n) and one from father (n) - together form a 2n pair!

Interphase

Growth and Development stage

IMPORTANT: Chromosomes replicate forming sister chromatids

Meiosis 1

Division of nucleus (P1, M1, A1, T1)

SEPARATION OF HOMOLOGOUS PAIRS

Interkinesis

Division of cytoplasm and organelles to form 2 cells

Meiosis 2

Division of nucleus (P2, M2, A2, T2)

Separation of sister chromatids

Cytokinesis

Division of cytoplasm and organelles to form 4 cells

“Crossing Over” in Tetrads (Prophase 1)

Non-sister chromatids (Mom and Dad chromosomes) exchange genetic information

Chromosomes formed are different from the original

Leads to variation and diversity in offspring

Gametogenesis

Forming gametes

Human Spermatogenesis

Formation of 4 sperm

Occurs in 2 testes or reproductive organs

Human Oogenesis

Formation of 1 egg (ovum) and 3 polar bodies that die

Occurs in 2 ovaries or reproductive organs

Polar bodies

A cell separates from the immature ovum during meiosis and cannot be fertilized (typically die)

Genotype

Gene that code for a trait

Phenotype

Trait that is shown

Physical expression of genes, outward appearence

Allele

Alternate version of genes

Accounts for variations in inherited characters

Different alleles vary somewhat in the sequence of nucleotides at the specific locus of a gene

Allele Set

True Genetic makeup of the chromosome

(Eye Color - Trait) (Red, white - Alleles)

P1 Generation

First Parents

F1 Generation

First offspring/1st gen (children)

F2 (Fn)

Second set of offspring (grand)/2nd gen

Test Cross

Crossing an unknown genotype (dominant phenotype) with a known recessive

Punnett Square

A table to help us see the genetic probabilities of a cross

Trait

Characteristic, Feature

Incomplete dominance

Hybrid is a blend of traits

Example:

Fr = Red

Fw = White

FrFw = PINK

The heterozygous creates a third phenotype

Every genotype has its own

phenotype

If both alleles are present and the two alleles differ

Then the dominant allele is fully expressed in the organism’s appearance

The other recessive allele has no noticeable effect on the organism’s appearence

Only see recessive if it is a

double recessive

Homozygous

2 of the same alleles

BB=Dominant, bb=recessive

Heterozygous

Hybrid condition

2 different alleles

Bb appears dominant

Normal vision female

XCXC

Carrier female (Heterozygous)

XCXc

Color blind female

XcXc

Normal vision male

XCY

Colorblind male

XcY

A is dominant over

O

B is dominant over

O

AB is

codominant

Blood type A (Phenotype)

AA or AO (Possible Genotypes)

Blood type B (Phenotype)

BB or BO (Possible Genotype)

Blood type AB (Phenotype)

AB (Possible Genotypes)

Blood type O (Phenotype)

OO (Possible Genotype)

With RH

Positive

Without RH

Negative

Polygenic Traits

Many genes make up the final appearence

Examples include skin, eye, hair color

Karyotype

Arranging homologous pairs from largest to smallest excluding the sex chromosomes

Autosomes

#1-22 for all traits except sex

Sex chromosomes

Pair #23 XX (Female) or XY (Male)

Nondisjunction

Chromosomes fail to “disjoin” or separate

Trisomy

Zygote with 3 of ONE Type of Chromosomes

Monosomy

Zygote with 1 of one type

Down Syndrome has

3 #21 Chromosomes

Klinefelter’s Syndrome

has an extra X chromosome

Turner Syndrome

Has only one X chromosome

XO sex chromosome instead of XX female or XY for male

Law of Dominance

Example of simple inheritance where dominant allele is expressed and recessive is masked. Can occur on autosomes or sex chromosomes (X and Y)

Incomplete Dominance

When one dominant allele and one recessive allele are inherited from either parent, the heterozygous offspring will exhibit a blending of those two alleles

Codominance

Expression of both alleles at the same time. Phenotypes of both homozygous traits are equally expressed in the offspring.

Sex linked traits

Traits controlled by genes located on sex chromosomes (Colorblindness and hemophilia, these conditions are recessive to normal vision and blot clotting)

Multiple alleles

Traits are controlled by more than two ALLELES (Three for Blood Types, or Four alleles of a single gene, control fur coat color in rabbits)

Pedigree

Graphic representation of an individual’s family tree, which permits patterns of inheritance to be recognized

A dominant pedigree is either

Shaded or not shaded in

A recessive pedigree has

heterozygous (Half Shaded in)

Mendel’s Law of Segregation

the parental genes must separate randomly and equally into gametes during meiosis so there is an equal chance of the offspring inheriting either allele. No allele is favored or has an advantage over another.

Mendel’s law of independent assortment

Inheriting an allele has nothing to do with inheriting an allele for any other trait. The alleles from parents are passed on independently to the offspring. After fertilization, the resulting zygote(s) can end up with any combination of chromosomes

Organ that produces egg cells

Ovaries