Unit 4

Chapter 12

  • centromere - narrow waist of the duplicated chromosome

    • sister chromatids will seperate

  • cytokinesis - division of the cytoplasm

  • binary fission - prokaryotes dividing

  • phosphorylate - bring to a higher energy state

Interphase

  • most of a cell’s life

  • G1 - duplicates cell parts; if it gets through G1 good chance of cell division

    • checkpoint - does it have enough stuff to synthesize DNA

      • either apoptosis or G0

    • most important

    • no dna damage, p53 is broken down

    • too much p53 initiates apoptosis

  • S - (synthesis) - duplicates chromosomes specifically

  • G2 - double checks DNA replication

    • checkpoint - did the cell make mistakes in making DNA

      • apoptosis or mitosis

  • M - mitosis and cytokinesis

    • checkpoint - checks if all sister chromatids are attached to the spindle microtubules

Cyclins and Cyclin dependent kinases

  • when the two link up they make mitosis promoting factor (MPF)

    • MPF is made of a cyclin, a Cdk (kinase) and a phosphate group

  • CDK always there, signal later breaks down the cyclin

Growth Factors

  • platelet-derived growth factor (PDGF)

    • platelets cause cells to clot

density dependent inhibition - when crowded cells send signal to stop dividing

anchorage dependence - must be attached to substratum in order to divide

  • blood cells do not have anchorage dependence because they are always moving

There are proteins or enzymes that are necessary to make things go

  • different checkpoints

Mitosis

  • prophase

  • prometaphase

  • metaphase

  • anaphase

  • telophase

Chapter 13

  • life cycle - birth to time of reproduction

  • human somatic cells - non reproductive cells

  • karyotype - ordered display of the chromosomes in a cell

  • homologous chromosome - chromosomes that have the same genes in the same positions

  • sex chromosomes - determine the sex of the individual, called x and y

  • remaining 22 chromosomes - autosomes

  • diploid cell - (2n) has two sets of

    • first diploid cell is a zygote

Meiosis I

  • first part of cycle

  • two daughter cells per round

  • reductional division

  • makes two different cells

    • Prophase 1

      • DNA has been copies

      • duplicated sister chromatids

    • Metaphase 1

      • crossing over - chiasmata

      • microtubules

    • Anaphase 1

      • can be pulled apart either color either way

    • Telophase 1 and Cytokinesis

      • each half of the cell has a haploid set of chromosomes

Meiosis II

  • like mitosis

  • no crossing over

  • no identical cells

  • end with 23 chromosomes in every cell

  • reduces the number of chromosomes from two of each to one of each

Plants

  • bryophytes

  • ferns

  • gymno

Four steps plant went through to dominate planet

  • movement onto land

    • bryophytes

  • tissues

    • true tissures, (ferns)

    • move water from roots to shoots, sint have to be small

  • gymnosperm

    • seed (conifer tree)

  • angiosperms

    • coevolved to insects, ability to reproduce

Genes

P generation - parental generation

F1 - hybrid offspring

Law of Segregation

  • ratio of 3:1 purple to white in F2

  • when gametes are produced, two copies of each allele segregate so that offspring inherit only one allele

  • Four concepts of Mendel

    • two different versions of genes and the alternate versions are called alleles

    • if the alleles differ, one is the dominant and one is recessive

    • law of segregation

    • possible combinations are shown using punnett square

    • Law of independent assortment - the allele a gamete receives for one gene does not influence the allele received for another gene

  • homozygous

  • heterozygous

  • phenotype - appearance

  • genotype - letters/genes

  • test-cross - breeding the mystery individual with a homozygous recessive individual

  • monohybrid cross - Hh x Hh

  • dihybrid cross - YRYr x YRYr

    • The phenotypic ratio will always be 9:3:3:1

complete dominance - dominant gene

codominance - mix

incomplete - both show up

Tay-Sachs: fatal disease, buildup of lipids in brain

Non-nuclear inheritance

  • disorders that come from the DNA in mitochondria

    • less energy

    • always comes from the mom

Pedigree Analysis

  • circles for females

  • square for males

  • shaded for affected

  • consanguineous (inbreeding) the recessive traits will show up more

Chapter 15

  • Thomas Hunt morgan studied fruit flies and figured out that some genes are linked and some are on sex chromosomes

    • only the males had white eyes (recessive) in F2 generation

      • proves the gene is on the x chromosome

  • x linked disorders are almost always, not usually y linked traits

  • The ultimate source of variations is mutations in the DNA

  • Nondisjunction is when chromosomes don't separate properly during cell division. This can cause genetic disorders because the cells end up with too many or too few chromosomes.

  • genomic imprinting - the silencing of certain genes that are stamped with an imprint during gamete production

  • Methylation is a process that happens in our bodies and other living things. It's like adding a small chemical tag called a methyl group to our DNA or proteins. This tag can change how our genes work, kind of like turning a switch on or off. It helps control which genes are active and which ones are not. Think of it as a way for our body to make different instructions for different cells, like telling them what to do and how to behave.