Glenco chapters 9 & 10
Reproduction
Asexual: The production of offspring by a single parent.
Sexual: The production of offspring by a combination of genetic material from
2 parents.
Asexual Reproduction
Binary fission: “Dividing in half”: 1 parent splits evenly into 2 daughter
cells.
Budding: Parent organism divides into 2 unequal parts.
Regeneration
The regrowth of body parts from pieces of an animal (Planaria)
DNA
Chromosome: Structure that contains DNA during cell division.
Sister chromatids: Chromosome duplication. (2 copies of DNA)
Daughter Chromosomes: 2 identical copies of original chromosome
Centromere: The region where 2 chromatids are joined together
Cell Cycle
Interphase: Cell doing regular cell things.
Mitosis: Genetic material and cell duplicates.
Cytokinesis: Cytoplasm divides and cell splits into 2 identical cells.
Mitosis consists of four distinct phases: Prophase, Metaphase, Anaphase,
Telophase & cytokinesis
Mitosis
Cytokinesis:
In animals cleavage furrow pinches the cell into 2 identical cells.
In plants the cell plate joins with existing cell wall to form a new cell
wall between the 2 new cells.
So How Do We Remember The Order of Mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
I Pee More After Tea!
Cancer Cells: Growing Out of Control
Normal plant and animal cells have a cell cycle control system
When the cell cycle control system malfunctions
Cells may reproduce at the wrong time or place
A benign tumor may form
Cancer Treatment
Cancer treatment
Radiation therapy disrupts cell division
Chemotherapy involves drugs that disrupt cell division
Genetics
The science of heredity.
Inherited characteristics and patterns
Predictions of ratios for a trait in offspring.
How chromosomes effect inheritance.
Chromosome Lingo
Homalogous: 2 pair of matching chromosomes for the same characteristic.
Autosomes: Body cell chromosomes (22 pairs of autosomes in humans)
Sex chromosomes: X & Y genes in humans. ( 1 pair of sex chromosomes)
Diploid / Haploid
Diploid cells: 2 homologous sets of chromosomes (2n).
Somate (body cells)
Diploid # for humans is 46
Haploid cells: 1 set of chromosomes (1n).
Gametes (egg & sperm)
Haploid # for humans is 23
Fertilization
Fertilization: The fusing of 2 haploid nuclei
Zygote: The resulting diploid cell from fertilization
Meiosis
In meiosis
Haploid gametes are produced in diploid organisms
Two consecutive divisions occur, meiosis I and meiosis II, preceded by
interphase
Crossing over occurs
Meiosis I
Prophase I:
Synapsis: Homologous chromosomes, each has 2 sister chromatids, pair up
forming a tetrad.
Each tetrad has 4 chromatids.
Crossing over can occur (exchanging of segments between chromosomes)
The rest of prophase I is similar to mitosis.
Genetic Variation
Offspring of sexual reproduction are genetically different from their parents
and from one another
Assortment of chromosomes
Genetic recombination: A chromosome with a different combination than the
parent
Crossing over
Gregor Mendel Father of Genetics
Mendel’s principle of segregation:
Pairs of genes segregate (separate) during gamete formation; the fusion of
gametes at fertilization pairs genes once again.
Mendel’s principle of independent assortment:
Each pair of alleles segregates independently during gamete formation.
Genetics Lingo
P generation: Parental
F1: Offspring from P Gen.
Allele: Alternative forms of genes.
Dominant allele & recessive allele.
Monohybrid cross: Cross with only 1 trait.
Dihybrid cross: 2 trait cross
Homozygous: A pair of identical alleles for a given trait (PP or pp capital
letter designates dominant, lower case recessive).
Heterozygous: 2 different alleles for a given trait (Pp).
Even More Genetics Lingo
Phenotype: Physical appearance for the trait. (Purple or white flower).
Genotype: The genetic make up for the given trait (PP. Pp, or pp)
Probability
Probability scale 0 to 1
The probabilities of all outcomes must add up to 1.
Coin toss: chance of heads 1/2 chance of tails 1/2 probabilities add up to 1
Deck of cards: 1/52 chance of drawing jack of diamonds; 51/52 chance of
drawing any card other than jack of diamond
Complete Dominance
Dominant allele is expressed even in heterozygous individuals.
P = purple, p = white
Pp individual phenotype will be purple.