SUNY WCC BIOL 115 Unit 4 Exam

Unit 4 Part A: How Cells Divide

Eukaryotic cells usually have \___ to \___ chromosomes in their body (\___) cells

10 to 50, somatic

Humans have \___ nuclear chromosomes in \___ near identical pairs

46, 23

Karyotype

Particular array of chromosomes in an individual organism

Karyotypes are arranged according to \___, \___ properties, location of \___, etc

Size, staining, centromere

2n refers to

Diploid cells

n refers to

Haploid cells

Humans are diploid (2n), meaning they have:

2 complete sets of chromosomes (2n), 46 total chromosomes

Haploid (n)

One set of chromosomes, 23 in humans

A pair of chromosomes are \___

Homologous

You get one \___ from the mother and one \___ from the father

Homologue, homologue

Chromosomes are composed of \___, a complex of \___ and \___

Chromatin, DNA and protein

RNA is also associated with chromosomes during \___ \___

RNA synthesis

DNA of a \___ \___ is one long continuous double-stranded fiber

Single chromosome

The typical human chromosome is \___ \___ nucleotides long

140 million

In the non dividing nucleus, \___ is not expressed but \___ is expressed

Heterochromatin, euchromatin

DNA is wound around \___ proteins

Histone

The DNA duplex is coiled around \___ histone proteins every \___ nucleotides

8, 200

Histones are \___ charged and strongly attracted to the \___ charged phosphate groups of \___

Positively, negatively, DNA

Histones play a role in \___ DNA and regulating \___ \___ (whether a gene is turned on or off)

Compacting, gene expression

During \___ \___, the chromosome becomes very compact and displays a complex organization beyond that of the \___, structurally. This is the only time it is visible in light microscopy.

Cell division, nucleosome

Lower levels of eukaryotic chromosome organization (composed of?)

Nucleosome, beads on a string, DNA double helix

Higher levels of eukaryotic chromosome organization (composed of?)

Mitotic chromosome, rosettes of chromatin loops, chromatin loop, solenoid

Prior to replication, each chromosome is composed of a \___ \___ \___

Single DNA molecule

After replication, each chromosome is composed of \___ \___ \___ \___ held together by \___ proteins

2 identical DNA molecules, cohesin

Chromosomes composed of 2 identical DNA molecules become \___ in light microscopy as the two \___ connected in the middle become more \___

Visible, chromatids, condensed

One chromosome consists of two sister \___

Chromatids

Eukaryotic cell cycle

G1, S, G2, M, C

Interphase includes \___, \___, and \___

G1, S, G2

G1 (gap phase 1)

Primary growth phase, longest phase

S (synthesis)

Replication of DNA

G2 (gap phase 2)

Organelles replicate, microtubules organize

In G2, \___ coil more tightly using \___ proteins; \___ replicate; \___ synthesis

Chromosomes, motor, centrioles, tubulin

M (mitosis) is subdivided into \___ phases

5

C (cytokinesis)

Separation of 2 new cells

Centromere

Point of constriction

Kinetochore

Attachment site for microtubules

Each sister chromatid has a \___

Centromere

Chromatids stay attached at centromere by \___ \___

Cohesin proteins

The 5 phases of mitosis

Prophase, prometaphase, metaphase, anaphase, telophase

Prophase: individual condensed \___ first become \___ with the light microscope

Chromosomes, visible

\___ continues throughout prophase

Condensation

Prophase: \___ continues, the \___ \___ assembles and the \___ \___ breaks down

Condensation, spindle apparatus, nuclear envelope

Prometaphase: transition occurs after disassembly of the \___ \___

Nuclear envelope

Prometaphase: \___ attachment occurs when a second group grows from \___ and attaches to \___. Each \___ \___connects to opposite poles

Microtubule, poles, kinetochores, sister chromatid

Prometaphase: \___ begin to move to the center of the cell

Chromosomes

Metaphase: alignment of chromosomes along the \___ \___ which is not an actual structure but a future axis of \___ \___

Metaphase plate, cell division

Anaphase: begins when \___ split; a key event is the removal of \___ \___ from all chromosomes; \___ \___ are pulled to opposite poles

Centromeres, cohesin proteins, sister chromatids

Telophase: the \___ \___ disassembles; \___ \___ forms around each set of sister chromatids, now called \___; \___ begin to uncoil

Spindle apparatus, nuclear envelope, chromosomes, chromosomes

Cytokinesis: \___ of the cell into equal halves

Cleavage

The current view of the cell cycle integrates two concepts: the cell cycle has \___ irreversible points and the cell cycle can be put on hold at specific points called \___

Two, checkpoints

The two irreversible points of the cell cycle

Replication of genetic material, separation of the sister chromatids

What happens at the cell cycle checkpoints?

Process is checked for accuracy and can be halted if there are errors, allows cells top respond to internal and external signals

What are the three cell cycle checkpoints?

G1/S, G2/M, late metaphase (spindle)

During the G1/S checkpoints, the cell "decides" to \___, it is a primary point for \___ \___ influence

Divide, external signal

During the G2/M checkpoints, the cell makes a commitment to \___ and assesses success of \___ \___

Mitosis, DNA replication

During the late metaphase (spindle) checkpoint, the cell ensures that all \___ are attached to the \___

Chromosomes, spindle

Cancer

Unrestrained, uncontrolled growth of cells

Cancer is the failure of \___ \___ \___

Cell cycle control

Two kinds of genes can disturb the cell cycle when they are mutated:

Tumor-suppressor genes and proto-oncogenes

Unit 4 Part B: Sexual Reproduction and Meiosis

Any cell in the body can go through \___

Mitosis

The only cells that go through meiosis are \___ and \___ cells, or \___

Sperm and egg, gametes

A haploid sperm + a \___ egg \= a \___ zygote

Haploid, disploid

A diplod zygote contains a paternal \___ and a maternal \___

Homologue, homologue

The replication of gametes is called \___

Meiosis

A mother will have the \___ chromosome

X

A father will have the \___ chromosome

Y

What are the two ways meiosis creates diverse gametes?

Through the random orientation and crossover of two homologous chromosomes

In meiosis 1,

Homologous chromosomes separate

In meiosis 2,

Sister chromatid pairs separate and four nuclei are produced

Meiosis, unlike mitosis, produces genetic \___

Diversity

Memorize slide 12 steps

Nondisjunction

Chromatids/chromosomes fail to separate

If nondisjunction occurs during meiosis 1,

Both members of a pair of homologous chromosomes go into the same daughter cell

If nondisjunction occurs during meiosis 2,

Sister chromatids fail to separate

Trisomy

Three copies of a chromosome

Monosomy

Single copy of a chromosome

What syndrome occurs with trisomy?

Down syndrome

Can a person develop without X chromosomes (only have Y chromosomes)?

No, they would not exist

Unit 4 Part C: Patterns of Inheritance

Before the 20th century, two concepts were the basis for ideas about heredity:

Heredity occurs within species and traits are transmitted directly from parent to offspring

Gregor Mendel used peas because peas have/are/can:

Hybrids, varieties, easy to grow, self fertilize or cross-fertilize

Mendel's three stages of experimental method: produce \___-\___ \___ for each trait he was studying, \___-\___ true-breeding strains having alternate forms of a \___, allow the hybrid offspring to \___-\___ for several generations and \___ the number of offspring showing each form of the \___

true-breeding strains, cross-fertilize, trait, self-fertilize, count, trait

A flower has both \___ and \___ reproducing parts

Male and female

Male parts of a flower

Anthers

Female parts of a flower

Carpel

Monohybrid crosses

Crosses to study only two variations of of a single trait

Mendel produced true-breeding pea strains for 7 different traits, each trait had \___ variants: \___

Two, flower color, seed color, seed texture, pod color, pod shape, flower position, plant height

F1 generation (first \___ \___), offspring produced by crossing 2 \___-\___ \___

Filial generation, true-breeding strains

For every trait Mendel studied. all F1 plants resembled only \___ \___, referring to this trait as \___ while the alternate trait was \___

One parent, dominant, recessive

F2 generation (second \___ \___), offspring resulting from the \___-\___ of F1 plants

Familial generation, self-fertilization

Although hidden in the F1 generation, the \___ \___ had reappeared among some F2 individuals. The counted F2 \___ proportion of dominant to recessive traits was always a \___:\___ ratio, but the actual F2 \___ proportion is \___:\___:\___, consisting of \___ true-breeding dominant plant(s), \___ not true-breeding dominant plant(s), and \___ true-breeding recessive plant(s), or \___:\___:\___

Recessive trait, phenotypic, 3:1, genotypic, 1:2:1, 1, 2, 1, PP:Pp:pp

Mendel's 5 Element Model:

1.Parents transmit \___ \___ (\___)

2.Each individual receives one copy of a gene from \___ \___

3.Not all copies of a gene are \___

4.Alleles remain \___ - no \___

5.Presence of allele does not guarantee \___

Discrete factors (genes), each parent, identical, discrete, blending, expression

Allele

Alternative form of a gene