Chapter 2

Question 1

Prokaryote

Answer 1

Unicelluar, no membrane, bacteria

Question 2

Eukayote

Answer 2

Multicellular and unicellular with membranes, DNA has tightly packed chromosomes, Genetic material forms a nucleus

Question 3

virusus

Answer 3

Neither prokaryotic
nor eukaryotic
* Outer protein coat
surrounding nucleic
acid

Question 4

Cell reproduction

Answer 4

Successful cell reproduction requires:
* Genetic information must be copied
* Copies must be separated from each other
* Cell must divide

Question 5

Binary Fission

Answer 5

Simple division:
separation of replicated
circular chromosome
* Origin of replication
* Each new cell has an
identical copy of the
original chromosome.

Question 6

Eukaryotic Cell Replication

Answer 6

DNA replication
* Copy separation
* Division of the cytoplasm
Nucleus internal scaffolding – nuclear
matrix

Question 7

Homologous Pair

Answer 7

• Humans have 23 homologous pairs!
• The two chromosomes are usually alike in structure and size.
• Each carries genetic information for the same
  set of hereditary characteristics (except sex
  chromosomes

Question 8

Ploidy

Answer 8

• Diploid cells carry two sets of genetic information.
• Haploid cells carry one set of genetic information
• Polyploid – cells that contain more
  than two sets.

Question 9

Diploid cells have

Answer 9

Two sets of chromosomes

Question 10

Chromosome Structure

Answer 10

Centromere: attachment
point for spindle
microtubules

Pair of telomeres:tips of a linear
chromosome
Protect and stabilize the
chromosome ends.

Origin of Replicationn: where
the DNA synthesis begins (not
easily observed by
microscopy

Question 11

Interphase

Answer 11

• G1
  /S checkpoint: regulated decision point
• S: DNA synthesis
• G2
  /M checkpoint: passed if DNA is completely replicated and undamaged

Question 12

M Phase and Cytokinesis

Answer 12

• Mitosis: separation of sister chromatids
• Cytokinesis: separation of cytoplasm

Question 13

Counting Chromosomes
and DNA Molecules

Answer 13

1) # of chromosomes = # of functional centromeres!
2) # of DNA molecules
Determine if sister chromatids are present!
a) If sister chromatids are present
(chromosome has replicated), then the number of
DNA molecules is twice the number of chromosomes.
b) If absent, the DNA molecules count is the
same as chromosome!

Question 14

Mitosis vs. Meiosis

Answer 14

Mitosis:
* Single nuclear division with typically a single cell division
* Same chromosome number in new cells as original
* Produces genetically identical cells

Meiosis:
* Two divisions
* New cells have half the number of chromosomes as original
* Produces genetically variable cells (crossing over)

Question 15

Sexual Reproduction and
Genetic Variation

Answer 15

Meiosis: the production of haploid gametes

Fertilization: the fusion of haploid gametes

Genetic variation: consequences of meiosis

Question 16

Meiosis

Answer 16

• Interphase: DNA synthesis and chromosome
  replication phase
• Meiosis I: separation of homologous
  chromosome pairs, and reduction of the
  chromosome number by half
• Prophase I
• Synapsis
• Tetrad
• Crossing over―exchange of genetic information, the first
  mechanism of generating genetic variation in newly formed
  gametes
  Metaphase I
• Anaphase I ―second mechanism of generating genetic
  variation in the newly formed gametes
• Telophase I
• Interkinesis – nuclear membrane re-forms, spindle breaks
  down, chromosomes relax
• Meiosis II: separation of sister chromatids, also
  known as equational division
  Prophase II
• Metaphase II
• Anaphase II
• Telophase II

Question 17

Meiosis in animals

Answer 17

• Spermatogenesis: male gamete production
• Oogenesis: female gamete production