Biology H - Chapter 8 (INCOMPLETE)

The Cellular Basis of

Reproduction and Inheritance

Chapter 8

Types of Reproduction

●Asexual Reproduction

○One parent

○Identical offspring

●Sexual Reproduction

○Two parents

○Variations in traits

Importance of Cell Division

●Reproduction at the cellular level

●Produces daughter cells identical to each other and the parent cell

●Requires the duplication of chromosomes

●Growth, repair, and replacement

Section 8.1 Review

Multiple Select

What are the two types of Reproduction?

• Asexual

• Mitosis

• Sexual

• Meiosis

Multiple Choice

Which type of reproduction contains only one parent?

• Asexual

• Sexual

Multiple Choice

Asexual reproduction produces _____ offspring.

• similar

• identical

• different

• multiple

Multiple Choice

Which type of reproduction contains two parents?

• Asexual

• Sexual

Multiple Choice

Sexual reproduction produces offspring with _____ traits

• multiple

• similar

• various

• identical

Multiple Choice

Cell Division is reproduction at the _____ level.

• Molecular

• Chemical

• Cellular

• Organelle

Multiple Choice

Cell division produces _____ cells that are identical to each other and the _____ cell.

• daughter; parent

• son; parent

• son; mother

• daughter; father

Multiple Choice

Cell division requires the _____ of _____.

• division; chromosomes

• multiplication; centrosomes

• duplication; chromosomes

• duplication; centrosomes

Multiple Choice

Cell division is the growth, repair, and _____ of cells

• changing

• exchange

• resurrection

• replacement

Binary fission

●Prokaryotes - Asexual

●Prokaryotic chromosome

○Single, circular DNA molecule associated
with proteins

○Smaller than eukaryote

●Steps:

○Duplication of chromosome & separation of
copies

○Cell elongates

○Division

Eukaryotic Cells

●Eukaryotic cells

○More complex and larger than prokaryotic cells

○More genes

○Multiple chromosomes; number differs by species

●Chromatin

●Sister chromatids

●Centromere

The Cell Cycle

●Interphase

○G1

○S

○G2

●Mitotic Phase

○Mitosis

■Prophase

■Prometaphase

■Metaphase

■Anaphase

■Telophase

○Cytokinesis

Complete the cell cycle diagram by writing the correct name of
each phase on each line.

Mitotic Spindle

●Required to divide the chromosomes

●Guides separation of the two sets of chromosomes

●Composed of microtubules and associated proteins

●Spindle microtubules emerge from centrosomes

© 2015 Pearson Education, Inc.

Figure 8.5-1

Prophase

Prometaphase
INTERPHASE
MITOSIS

Centrosomes
Centrosome

Chromatin

Nuclear
envelope

Plasma
membrane

Early mitotic
spindle

Chromosome, consisting
of two sister chromatids

Centromere

Fragments of
the nuclear envelopeKinetochore

Spindle
microtubules

© 2015 Pearson Education, Inc.

Figure 8.5-6

Anaphase
MITOSIS

Metaphase

Telophase and Cytokinesis

Metaphase plate

Mitotic spindle
Separated
chromosomes

Cleavage
furrow

Nuclear
envelope
forming

Cytokinesis

●Cytoplasmic division

●Animal Cells vs Plant Cells

Label the
diagram

Anchorage, cell density, and chemical
growth factors affect cell division

Cell division controlled by:

●Anchorage dependence

●Density-dependent inhibition

●Essential nutrients

●Growth factors

Cell Cycle Control System

●Checkpoints in the cell cycle can
stop an event or signal an event to
proceed.
○

G1

○

G2

○

M

Figure 8.8b

Extracellular fluid

G2

G1

S

M

G1

checkpoint

Plasma membrane

Control
system

Growth
factor

Relay proteins

Receptor
protein

Signal
transduction
pathway

Cytoplasm

Cancer

●Cancer Cells

○Do not listen to normal signals that regulate cell cycle

○divide excessively and invade other tissues of the body.

●Tumor

○Benign

○Malignant

■Metastasis

●Naming

●HeLa Cells

●Treatments

Do Now: The four circles below represent a cell going through mitosis. Draw four
chromosomes as they go through PMAT. Label each phase and describe what is happening.

Meiosis and Crossing Over

8.11-8.17

Chromosomes are Matched into Homologous Pairs

●

Somatic cells vs. sex cells

●

Autosomes vs. sex chromosomes

●

Homologous chromosomes/homologs
○Size, Centromere position, Staining pattern

●Locus (pl. loci)

Ploidy

●Somatic cells

○Diploid (2n)

●Gametes

○Haploid (n)

●Fertilization

●Zygote

Organism

Haploid #
(N)

Diploid#
(2N)

Amoeba

N=25

Earthworm

N=18

Fern

2N = 1010

Hamster

N=22

Onion

2N = 16

Fill in the haploid
or diploid # for
each organism in
the table

Gametes are made by meiosis

●Happens in the ovaries and testes

●Cuts chromosome number in half

●Meiosis Basics:

○Chromosomes duplicated during interphase

○Meiosis I: separates homologous chromosomes (diploid to haploid) (1 cell to 2
cells)

○Meiosis II: separates sister chromatids (2 cells to 4 cells)

Spermatogenesis and Oogenesis

●Spermatogenesis

○4 sperm

●Oogenesis

○Meiosis complete after fertilization

○Polar bodies

○1 ovum

Meiosis Cycle

●One DNA replication event but two cell divisions (Meiosis I and Meiosis II)
1.

Interphase

2.

Meiosis I (Homologous Chromosomes (tetrad) Separate)
●Prophase I, Metaphase I, Anaphase I, Telophase I and Cytokinesis

3.

Meiosis II (Sister Chromatids Separate)

● Prophase II, Metaphase II, Anaphase II, Telophase II and Cytokinesis

Key points of Meiosis

● The process results in 4 daughter cells
● Daughter cells are haploid (N)
● Daughter cells have unique combinations of chromosomes

Similarities and Differences Between Mitosis and Meiosis

3 Sources of Genetic Variation

●Independent orientation of chromosomes during metaphase I

●Random fertilization

●crossing over during prophase I

Genetic variation in gametes

●Results from:

○Independent assortment

■Chromosomes independently align
at the cell equator during
metaphase I

○Random fertilization

■Combination of each unique
sperm with each unique egg
increases genetic variability

Crossing over further increases
genetic variability

●Genetic recombination

●Crossing over

○Exchanging corresponding segments between nonsister
chromatids of homologous chromosomes

○Nonsister chromatids join at a chiasma (pl. chiasmata), the site of
attachment and crossing over

○Corresponding amounts of genetic material are exchanged
between maternal and paternal (nonsister) chromatids.

Do Now: Draw two homologous pairs of chromosomes (in different colors for maternal and paternal)

in these diagrams to illustrate what happens during these three phases of meiosis, don’t forget to
show crossing over.