Chap 12, 13, 14, 15

Fundamental Characteristics of Life

Cells, Replication, Information, Energy, Evolution

M Phase

Dividing phase of cell cycle

Interphase

Chromosomes are uncoiled and cells grow

Interphase

Cells spend the most time in this phase

S Phase

Chromosomes get duplicated/DNA is synthesized in this phase of interphase

Gap Phase

Cells grow in this phase of interphase

Chromosome

A single, long double helix of DNA

Hisotnes

The proteins that chromosomes are wrapped around

Chromatin

The DNA protein material that compresses DNA into a compact unit during division

Gene

A section of DNA that codes for a specific RNA/protein

Cohesions

What attaches chromatids at their length

Centromere

Connects chromatids at the center once mitosis begins

Chromatid

One half of a duplicated chromosome

Replicated chromosomes

Consist of two copies of the same DNA double helix

Mitosis

The division of replicated chromosomes

Cytokinesis

The division of cytoplasm

46 Chromosomes

The number of chromosomes humans have

Spindle Apparatus

Moves apart replicated chromosomes and pull apart chromatids in late mitosis

Prophase

In what phase does the nucleolus disappear/melt away

Microtubules

What the spindle apparatus is made from

Microtubule Organizing Centers (MTOCs)

Defines the two poles and has polar microtubules that extend from each spindle pole

Centrosomes

MTOCs in animal cells each containing a pair of centrioles

Microtubules

Largest cytoskeletal elements that grow at plus ends

Prometaphase

Nuclear membrane disintegrates in this phase

Prometaphase

In this phase, microtubule fibers attach to chromosomes at kinetochores

Kinetochores

Protein structures that form on the centromere

Kinetochore Microtubules

Microtubules that attach to chromosomes

Prophase

In this phase, centrosomes migrate to cells opposing sides

Metaphase

Mitotic spindle is complete in this phase

Metaphase

Spindle moves chromosomes into linear formation on metaphase plate

Metaphase Plate

Where chromosomes line up during metaphase

Astral Microtubules

Hold spindle poles in place

Anaphase

In this phase, the centromere snaps and sister chromatids are separated

Anaphase

In this phase, the cell becomes elliptical as spindle fibers push at poles

Anaphase

Cohesions holding sister chromatids together split in this phase

Telophase

New nuclear envelope forms around each set of chromosomes in this phase

Cytokinesis

This phase occurs immediately after mitosis and forms two daughter cells

Cell plate

Formed in plants by vesicles to help in cytokinesis

Cleavage Furrow

Formed by a ring of actin + myosin filaments that shrink and tighten

Binary Fission

The way bacteria divides

Kinase

Enzyme that attaches a phosphate group from ATP to a protein

Phosphotase

An enzyme that removes a phosphate group from a protein

Gametes

Reproductive cells that consist of sperm and eggs in animals

Fertilization

When gametes unite to form a new individual

Meiosis

Nuclear division that leads to halving of chromosome number

Gametes

Cells produced by meiosis that contain half of original number of chromosomes

Autosomes

Non-sex chromosomes

Homologous Chromosomes

Chromosomes of the same type

Homologous Pairs

Contain the same genes in the same positions

Length, centromere position, staining pattern

What are the shared characteristics of homologous pairs?

Alleles

Can differ in homologs, different versions of a gene

Genetic Locus

Location of a particular gene on a chromosome, each has one allele on each homologue

Diploid (2n)

Having two homologs of each chromosome and two alleles of each gene

Haploid (n)

Having only one type of each chromosome and one alleles of each gene

Ploidy

Indicates the number of complete chromosome sets

Sister chromatids

Identical halves of a chromosomes that result from replication

Meiosis 1

Parent cell is diploid in this phase (2n) and contains a homologous pair of replicated chromosomes

Meiosis 2

Daughter cells are haploid in this phase (n) and contain just one homolog

Gametogenesis

The way in which daughter cells become eggs or sperm

Zygote

A diploid cell created through fertilization, each zygote receives a haploid chromosome set from mother and father

Early Prophase 1

In this phase, homolog pairs come together in pairing process called synapsis

Synapsis

The process of homolog pairs coming together

Bivalent/Tetrad

Homologous pairs joined by synapsis that consist of two homologs

Synaptonemal Complex

Proteins that hold a bivalent together

Late Prophase 1

Homologs separate in this phase but are attached at certain chiasmata

Chiasmata

The points at which homologs are attached during late prophase 1

Crossing over

Gives rise to kids that are genetically distinct from their parents during late prophase 1

Crossing over

Produces chromosomes with a combination of maternal and paternal alleles

Mitotic Phase

Includes mitosis and cytokinesis

Prophase

What phase of mitosis is this?

Metaphase

What phase of mitosis is this?

Telophase

What phase of mitosis is this?

Anaphase

What phase of mitosis is this?

Natural Selection

Explains how evolution occurs

Variation of characteristics, adaptations

Rules for natural selection

Genetic Recombination

the creation of new alleles, promoted by crossing over

Independent Assortment

Random Separation of homologous chromosomes during meiosis

Chiasmata

The point at which crossing over occurs between homologous pairs, not sister chromatids

Random Fertilization

Random union of gametes that ensures offspring will be genetically different from parent

Outcrossing

Gametes from different individuals, as opposed to self-fertilization

Trisomy 21

Scientific name for down syndrome

Sister chromatids move to the same pole in anaphase

How can a mistake occur in meiosis?

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during cell division, results in polyploidy

Polyploidy

When a normally diploid cell or organism acquires one or more additional sets of chromosomes, resulting in three or more times the haploid chromosome number

Oogenesis

Egg development in humans

Primary oocytes

Diploid precursors to eggs

Can be up to a 50 year wait for meiosis to reach completion for primary oocytes (50 years)

Why do more errors occur in females in meiosis?

Deleterious

A damaged gene

All offspring will inherit the gene

Why are deleterious genes bad for asexual reproduction?

Purifying selection

Natural selection against deleterious alleles

Chromosomal theory of inheritance

How genetic information is transmitted from one generation to the next

Blending Inheritance

Dated belief that parental traits blend so that their offspring have intermediate traits (ex. white + red = pink)

Inheritance of Acquired Characteristics

Dated belief that parental traits are modified through use and then passed on (ex. giraffe necks)

Garden pea

What Mendel used for his experiments

Polymorphic Traits

A trait that appears commonly in two or more different forms (ex. round vs wrinkly peas for the texture)

Cross Fertilization

Mendel’s process of removing male genitalia from a pea plant and moving pollen from another plant to it

Self-replication

How pea pod plants typically reproduce

Genes

Hereditary determinants for a trait

Alleles

The 2 versions of each gene that a human has

Phenotype

Observed characteristics of an organism