Lesson 6: The Cell DNA and Chromosomes

Question 1

Physical Composition of
DNA

Answer 1

• two long sugar-phosphate
  chains, in a
  double-helix configuration
• linked by pairs of nitrogenous organic bases at the sugar molecule of the chain
• connected by hydrogen bonds
• carries genetic information for cell replication

Question 2

What does DNA do

Answer 2

• Regulates all cellular activity to direct protein synthesis
• Determines a person’s characteristics by regulating the sequence of amino acids in the person’s constituent proteins during synthesis of
  these proteins
• Sequence of nitrogenous base pairs in a DNA molecule that constitutes the genetic code
• 2.9 billion base pairs
  Identifies who you are

Question 3

DNA Bases

Answer 3

• Purines
  Adenine
  Guanine
• Pyrmidines
  Thymine
  Cytosine
• Pairings
  A & T
  C & G

Question 4

Base Paring

Answer 4

• sequence of base pairing is the genetic code

Question 5

What is a chromosome

Answer 5

• tiny rod shaped bodies that are composed of protein and DNA
• normal people have 46
• reproductive/germ cells have 23

Question 6

What is a gene

Answer 6

Distinct segments of DNA that serve as the base unit of heredity
contains information responsible for directing cytoplasmic activity,
controlling growth and development of the cell, and transmitting hereditary
information
- control the formation of protiens through genetic coding

Question 7

Effects of radiation on the cell

Answer 7

• Behave abnormally or cell death

Question 8

Somatic Cells

Answer 8

2 of each gene on 2 different chromosomes
23 pairs of homologous chromosomes
46 pairs of chromosomes (diploid or 2n)

Question 9

Genetic/germ cells

Answer 9

• female
  oogonia (immature 2n / 46)
  eggs (n / 23)
• male
  Spermatogonia (immature 2n / 46)
  Sperm (gamete n / 23)

Question 10

Cell processes of division

Answer 10

• mitosis (somatic)
  -meiosis (genetic)

Question 11

Cellular Life Cycle

Answer 11

• interphase (cell growth before mitosis)
• S phase is when each DNA molecule is replicated and divided into 2 sister chromatids
• subphases of mitosis
  prophase
  metaphase
  anaphase
  telophase

Question 12

Synthesis Phase (S phase)

Answer 12

Each DNA molecule is replicated into 2 identical daughter
chromosomes
( I becomes X)

Question 13

Radiation Effects of mitosis

Answer 13

During metaphase cell division can be stopped and chromosome damage caused by radiation can be visualized under a microscope
* Results in an approximately equal distribution of all cellular material between the two daughter cells

Question 14

process of meiosis

Answer 14

During meiosis, sister chromatids exchange some
chromosomal material (genes) called crossover
* Crossover results in changes in genetic compositions and traits that can be passed on to future generations
Special type of cell
division that reduces
the number of
chromosomes in
each daughter cell to
half the number of
chromosomes in the
parent cell

Question 15

What is a diploid

Answer 15

2 gametes form a diploid zygote
- egg + sperm = zygote

Question 16

What is a haploid

Answer 16

The number of chromosomes in a gamete

Question 17

Zygote

Answer 17

becomes embryo