Exam 4 Learning Objectives (from Quizlet)

The process by which a single cell becomes two daughter cells. Requirements: Each daughter cell must receive the full complement of genetic material from the parent cell and the parent cell must be large enough to divide in two and provide sufficient cytoplasmic components to the daughter cells

Occurs in prokaryotes, look in notes for process.

Eukaryotes: genome larger and linear, DNA in nucleus; Prokaryotes: genome smaller and circular, DNA in cytoplasm

M phase: the time during which the parent cell divides into two daughter cells and Interphase: the time between M phases

lasts 10−14 hours, Cell makes preparations for division:
i. replication of DNA in the nucleus ii. increase in cell size. Phases: G1: the size and protein content of the cell increase in preparation for the S phase regulatory proteins are made and activated. S1: Synthesis (replication) of DNA, G2: the cell prepares for mitosis and cytokinesis, G0: No preparation, this phase is present in cell types that do not actively divide: liver and nerve cells

DNA is organized with histones and other proteins into chromosomes, Cells of the human body contain 46 chromosomes (23 pairs), Humans have 22 pairs of homologous chromosomes and 1 pair of sex chromosomes

Cells with one complete set of chromosomes are haploid, cells with two complete sets are diploid

Kinetochores: Ensure that each sister chromatid is attached to a microtubule radiating from one of the poles of the cell. Centromeres: Region where cell's spindle fibers attach. Chromatids: authorizes cells to store two copies of their information in preparation for cell division

Prophase: Chromosomes condense, and Centrosomes radiate microtubules and migrate to opposite poles. Prometaphase: Microtubules of the mitotic spindle attach to chromosomes. The nuclear envelope breaks down. Metaphase: Chromosomes align in the middle of the cell. Anaphase: sister chromatids separate and travel to opposite cells. Telophase: nuclear envelope reforms and chromosomes decondense.

The separation of the two daughter cells into separate cells.

cytokinesis in animals begins with a pinching inward of the cell membrane midway between the dividing cell's poles and the cleavage furrow uses the action of microfilaments
cytokinesis in plants begins with vesicles formed by the Golgi apparatus fuse at the midline of the dividing cell forming a membrane-bound cell wall called the cell plate

Occurs only in specialized germ cells that give rise to sperm and egg cells. Results in four daughter cells, containing half the number of chromosomes as the parent with each daughter cell genetically unique

Look at notes for this one

Sperm: all 4 daughter cells are used to make sperm cells, Egg: one is an oocyte and the other three are polar bodies.

gametes fuse to form a single cell called a zygote, restoring the original chromosome number (diploid)

Mitosis is a lot like the second stage of meiosis, except the chromosomes aren't crossed over and 2 daughter cells rather than 4 are produced. Meiosis involves crossing over and has two stages to create 2 daughter cells that further split up into two more.

Cyclins bind to and activate Cyclin-Dependent Kinases to control progression throughout the cell cycle.

G1/S Cyclin-CDK complex: active at the end of G1 and prepares the cell for the S phase. S Cyclin-CDK complex: Initiates DNA synthesis during the S phase and Activates protein complexes involved in DNA replication. M Cyclin-CDK complex: Active at end of G2 and beginning of M Initiates multiple events associated with mitosis.

DNA damage checkpoint: Checks for damaged DNA before it enters S phase. DNA replication checkpoint: checks for the presence of un-replicated DNA before the cell enters mitosis. Spindle assembly checkpoint: checks for attachment of all chromosomes to the spindle before the cell progresses with mitosis.

Normally p53 is not phosphorylated and is rapidly exported from the cell and degraded. But DNA damage activates protein kinases that phosphorylate p53 blocking the export process. As p53 levels increase, it acts as a transcription factor to turn on genes that inhibit the cell cycle. Inhibiting the cycle gives the cell more time to repair the damaged DNA.

Sugar P backbone, A-T 2 H bonds, G-C 3 H bonds

Semiconservative model: After DNA replication, the new DNA duplex consists of one parental strand and one new daughter strand. Conservative model: After DNA replication, the new DNA duplex consists of two newly synthesized daughter strands.

At the beginning of the experiment, both bands have heavy N and form a heavy N band. After one round of replication, parent still has heavy N, daughter has light N. Daughter DNA bands form an intermediate N band. After 2 rounds, half molecules have heavy half have light, and the other half are light, forming two bands one intermediate other light. If they had both been light, conservative would have been correct, but since it's half-light half intermediate it's semi-conservative cause the parent strand still exists.

Replication is catalyzed by DNA polymerase, highly conserved across species, synthesizes a new DNA strand from an existing template, and corrects mistakes in replication. Proofreading: DNA polymerase detects mispairing between nucleotides, When an error is detected, DNA polymerase removes the incorrect nucleotide and inserts the correct one in its place

The leading strand is constantly being formed but the lagging strand is formed in parts as it's facing the wrong way.

short, discontinuous polymers that make up the lagging strand.

Each new DNA strand begins with a short stretch of RNA that serves as a primer for DNA synthesis, Primase is an RNA polymerase that forms primers.

Helicase unwinds the duplex, Topoisomerase II relieves the stress of unwinding, Single-stranded binding proteins Prevent parental strands from reassociating.

Sequence of DNA nucleotides at which replication beings

Can start anywhere and goes along the circle in both directions. Same with linear but there are several origins that form replication bubbles as they replicate, when they meet other ones they fuse to form a larger one.

You have it memorized but the leading strand goes: 3' to 5', lagging goes 5' to 3' ends (backwards)

When replication ends, the leading strand has the whole strand replicated, the lagging strand does not because it removes the primer and then is missing parts of the template strand. Telomerase fixes this issue by containing RNA template that the lagging strand can code from so it gets the whole template strand. Each end of a eukaryotic chromosome is capped by a repeating sequence called the telomere.

the genetic makeup of a cell or organism vs. an individual's observable characteristics

sequence of DNA nucleotides that codes for a protein or functional RNA vs. the different forms of a gene, corresponds to differences in DNA sequences

The genes code for the physical features.

inherits the same allele of a particular gene (Homozygous) vs. inherits different alleles of a particular gene (Heterozygous)

the manner in which genetic differences among individuals are passed down from generation to generation

traits in the offspring resemble the average of those in the parents vs. that traits are not transmitted in inheritance, heredity units (aka genes) are transmitted

The physical appearance of the offspring in each successive generation is identical to the previous one

The female plants anothers are removed so as to prevent self-fertilization, mature pollen is collected from another flower and placed on the stigma, after fertilization a cloth bag is tied around the flower to prevent stray pollen from entering.

The dominant gene was more common in a 3:1 ratio of dominant to recessive.

only one allele for a particular trait ends up in an organism's gamete, separation of alleles into different gametes

When the chromosomes are separated during anaphase 1, there are 2 codes for A and 2 codes for a that is also separated, eventually making 4 gametes with 2 being A and 2 being a.

Plants with unknown genotypes are crossed with true-breeding recessive plants to find out their genotype if it is dominant it will be a 3:1 ratio in the phenotype.

Not all species exhibit the complete dominance that was observed in pea plants. P (C^R C^R x C^W C^W)= F1 (C^R C^W)= F2, the Result of segregation can be observed directly because the ratio of red: pink: white phenotypes are 1:2:1, which reflects the ratio of C^R C^R: C^R C^W: C^W C^W

Principle of Segregation: Individuals inherit two alleles of each gene, one from the mother and one from the father, and when individuals form reproductive cells, the two alleles separate equally into the eggs and sperm
Principle of Independent Assortment: The two alleles of each gene segregate into gametes independently of the two alleles of another gene.

It's the 16-square Punnett square, so it has seed colors and shapes for example. You know how to do this. But it's because of independent assortment that there are more traits you have to calculate because the Segregation of one set of alleles of a gene pair is independent of the segregation of another set of alleles of a different gene pair

Independent assortment of genes in different chromosomes reflects the fact that nonhomologous chromosomes can orient in either of two ways that are equally likely6y

Epistasis: genes modify the expression of other genes

pair of unmatched chromosomes that determine an individual's sex. The tips of the arms of X and Y share small region of homology. Almost none of X have counterparts in Y.

Meiosis in female results in all X, in male results in 1:1 ratio of X:Y

It's passed down on the X chromosome so females are usually hetero and males are usually homo