Module B Review 2 nd Quarterly Assessment Review Units 4 & 5.

Module B Review

2nd Quarterly Assessment ReviewUnits 4 & 5

BIO.B.1.1

• Describe the three stages of the cell cycle: interphase, nuclear division, cytokinesis.

• Describe the events that occur during the cell cycle: interphase, nuclear division (i.e., mitosis or meiosis), cytokinesis.

• Compare the processes and outcomes of mitotic and meiotic nuclear divisions.

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Cells divide at different rates.• The rate of cell division varies with the need for that type

of cell.

• Some cells are unlikely to divide (in Gap 0/G0 of the cell cycle)– Example: neurons

Cell size is limited.• Volume increases faster than surface area.

– Cells need to stay small to allow diffusion and osmosis to work efficiently.

Mitosis and cytokinesis produce two genetically identical daughter cells.

• Interphase: prepares the cell to divide. During interphase, the DNA is duplicated.

• Prophase: chromosomes condense, spindle fibers form, and the nuclear membrane disappears

Mitosis divides the cell’s nucleus in four phases.

• Metaphase: chromosomes line up in the middle of the cell

• Anaphase: sister chromatids are pulled apart to opposite sides of the cell

Mitosis divides the cell’s nucleus in four phases.

• Telophase– Two nuclei form at opposite ends of the cell, the

nuclear membranes reform, and the chromosomes uncoil back into chromatin

Cytokinesis differs in animal and plant cells.

• Cytoplasm separates– Animal cells: membrane pinches

the two new cells apart– Plant cells: a cell plate (new cell

wall) separates the two new cells

Cell division is uncontrolled in cancer.• Cancer cells form disorganized clumps called

tumors.– Benign tumors remain clustered and can be

removed.– Malignant tumors metastasize, or break away, and

can form more tumors.

5.4 – Asexual Reproduction

• Key Concept:– Many organisms reproduce by cell division.

Binary fission is similar to mitosis.• Asexual reproduction is the

creation of offspring from a single parent.– Binary fission produces two

daughter cells genetically identical to the parent cells.

– Binary fission occurs in prokaryotes.

Some eukaryotes reproduce by mitosis.

• Budding forms a new organism from a small projection growing on the surface of the parent.

• Fragmentation is the splitting of the parent into pieces that each grow into a new organism.

• Vegetative reproduction forms a new plant from the modification of a stem or underground structure on the parent plant.

Multicellular organisms depend on interactions among different cell types.• Tissues are groups of cells that perform a similar

function.• Organs are groups of tissues that perform a specific

or related function.• Organ systems are groups of organs that carry out

similar functions.

Specialized cells perform specific functions.

• Cells develop into their mature forms through the process of cell differentiation.

• Cells differ because different combinations of genes are expressed.

• A cell’s location in an embryo helps determine how it will differentiate.

6.1 – Chromosomes & Meiosis

• Key Concept:– Gametes have half the number of chromosomes

that body cells have.

You have somatic cells and gametes.

• Somatic Cells:– Are body cells– Make up all cells in body except for

egg and sperm cells– Not passed on to children

• Gametes:– Are egg or sperm cells– Passed on to children

Your cells have autosomes and sex chromosomes.

• Somatic cells have 23 pairs of chromosomes (46 total)– (1) Autosomes: pairs 1 – 22; carry

genes not related to the sex of an organism– (2) Homologous chromosomes: pair of chromosomes; get one from each parent; carry the same genes but may have a different form of the gene (example: one gene for brown eyes and one gene for blue eyes)

– (3) Sex chromosomes: pair 23; determines the sex of an animal; control the development of sexual characteristics

Somatic cells are diploid; gametes are haploid.

• Diploid (2n)– Has two copies of each

chromosome (1 from mother & 1 from father)• 44 autosomes, 2 sex

chromosomes– Somatic cells are diploid– Produced by mitosis

• Haploid (1n)– Has one copy of each

chromosome• 22 autosomes, 1

sex chromosome– Gametes are haploid– Produced by meiosis

Meiosis I• Occurs after DNA has been replicated

(copied)• Divides homologous chromosomes in four

phases.

Meiosis II• Divides sister chromatids in four phases.• DNA is not replicated between Meiosis I and

Meiosis II.

Mitosis Vs. Meiosis

Mitosis• One cell division• Homologous chromosomes

do not pair up• Results in diploid cells• Daughter cells are identical

to parent cell

Meiosis• Two cell divisions• Homologous chromosomes

pair up (Metaphase I)• Results in haploid cells• Daughter cells are unique

Sexual reproduction creates unique combinations of genes.

• Fertilization: Random, Increases unique combinations of genes

• Independent assortment of chromosomes– Homologous chromosomes pair randomly along

the cell equator• Crossing over

– Exchange of chromosome segments between homologous chromosomes

BIO.B.1.2

• Explain how genetic information is inherited. • Describe how the process of DNA replication

results in the transmission and/or conservation of genetic information.

• Explain the functional relationships between DNA, genes, alleles, and chromosomes and their roles in inheritance.

DNA

• There are 4 types of nitrogenous bases: thymine, adenine, cytosine, and guanine

• The nitrogen containing bases are the only difference in the four nucleotides.

Proteins carry out the process of replication.

• DNA serves only as a template. • Enzymes and other proteins do the actual

work of replication.• Process

1. Enzymes unzip the double helix.2. Free-floating nucleotides form hydrogen bonds

with the template strand.nucleotide

The DNA molecule unzips in both directions.

3. DNA polymerase enzymes bond the nucleotides together to form the double helix.

3. DNA polymerase

4. new strand 2. Nitrogen bases

1. Sugar Phosphate Backbone

• DNA replication is semi-conservative, meaning one original strand and one new strand.

original strand new strand

Two molecules of DNA

4. Two new molecules of DNA are formed, each with an original strand and a newly formed strand.

BIO.B.2.1

• Compare Mendelian and non-Mendelian patterns of inheritance.

• Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles).

Mendel laid the groundwork for genetics.

• Traits are distinguishing characteristics that are inherited. (eye color, hair color)

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

• Gregor Mendel showed that traits are inherited as discrete units.

The same gene can have many versions.

• A gene is a piece of DNA that directs a cell to make a certain protein.

• Each gene has a locus, aspecific position on a pair ofhomologous chromosomes.

• An allele is any alternative form of a gene occurring at a specific locus on a chromosome. – Each parent donates one

allele for every gene.– Homozygous describes two

alleles that are the same at a specific locus. Ex: (RR or rr)

– Heterozygous describes two alleles that are different at a specific locus.Ex: (Rr)

• Alleles can be represented using letters.

– A dominant allele is expressed as a phenotype when at least one allele is dominant.

– A recessive allele is expressed as a phenotype only when two copies are present.

– Dominant alleles are represented by uppercase letters; recessive alleles by lowercase letters.

Punnett squares illustrate genetic crosses.

• The Punnett square is a grid system for predicting all possible genotypes resulting from a cross.– The axes represent

the possible gametesof each parent.

– The boxes show thepossible genotypesof the offspring.

• The Punnett square yields the ratio of possible genotypes and phenotypes.

Other Forms of Inheritance

• Incomplete Dominance: 3rd new color (flowers)

• Co dominance: together (cattle)• Sex Linked: XX XY (color blindness)• Pedigrees: circles and squares• Blood Types AA Ai, BB Bi, AB, ii (multiple alleles)

Polygenic