General Biology 1 Course
Revision
Nucleotide structure
The basic unit of nucleic acids is nucleotide
RNA nucleotide
DNA nucleotide
Types of nitrogenous bases
18/12/1434
‫ زﯾﻧب اﻟﻣطﯾري‬/‫د‬
3
DNA structure
DNA
RNA
Sugar
Sugar in nucleotide is deoxyribose
Sugar in nucleotide is ribose
Structure
Double-stranded..
Single-stranded.
Base Pairing
Adenine links to thymine (A-T) and Adenine links to uracil (A-U) and
cytosine links to guanine (C-G).
cytosine links to guanine (C-G).
Location
DNA is found in the nucleus of a
cell.
Found in a cell's nucleus, its cytoplasm,
and its ribosome.
Chromosome Structure
Meiosis
Mitosis
Function
Sexual reproduction.
Genetically
Pairing of Homologs
Number of Divisions
Number of Daughter
Cells produced
Chromosome Number
Different
Yes
2
General growth and repair of the
body.
Identical
No
1
4 haploid cells
2 diploid cells
Reduced by half. (N)
Remains the same. (2N)
Steps
(Meiosis 1) Prophase I, Metaphase I,
Anaphase I, Telophase I; (Meiosis 2) Prophase, Metaphase, Anaphase,
Prophase II, Metaphase II, Anaphase II
Telophase.
and Telophase II.
Cytokinesis
Occurs in Telophase I and in Telophase II.
Occurs in Telophase.
Creates
Sex cells only: female egg cells or male
sperm cells.
Somatic cells.
Quiz
Choose the correct answer
• 1- The diploid chromosome number for the house fly is 12. The haploid number of
chromosomes found in their gametes would be
• A) 24
• B) 3
• C) 6
• D) 12
•
•
•
•
•
2- Each duplicated chromosome prior to division will be held together at a region called the:
A) tetrad
B) centromere
C) cross-over
D) chromatid
8
Quiz
Choose the correct answer
• 3- Prior to division, each chromosome is composed of two genetically identical
parts called ______ .
• A) centromeres
• B) nucleosomes
• C) chromatin
• D) sister chromatids
•
• 4- When does DNA replication occur in the cell cycle?
• A) interphase
• B) prophase
• C) metaphase
• D) anaphase
9
Quiz
Choose the correct answer
• 5- ______ consists of mitosis and interphase.
• A) Cell division
• B) The cell cycle
• C) The life cycle
• D) Oogenesis
• E) Spermatogenesis
• 6- Which of the following is the correct sequence of mitotic phases?
• A) metaphase, anaphase, telophase, prophase
• B) anaphase, prophase, metaphase, telophase
• C) prophase, anaphase, metaphase, telophase
• D) prophase, metaphase, anaphase, telophase
10
Quiz
Choose the correct answer
•
•
•
•
•
•
•
•
•
•
•
•
7- During ______ , the chromosomes first become visible.
A) interphase
B) prophase
C) metaphase
D) anaphase
8- During ______ , the nuclear envelope begins to fragment and the nucleolus begins
to disappear.
A) telophase
B) prophase
C) metaphase
D) anaphase
11
Quiz
Choose the correct answer
• 9- During ______ , chromosomes become indistinct but the nucleoli and the nuclear
envelope reappear.
• A) interphase
• B) prophase
• C) telophase
• D) anaphase
•
• 10- Prior to meiosis I, DNA replication occurs, and each chromosome has two sister
chromatids. Therefore, each chromosome can be called a ______ .
• A) homologous chromosome
• B) daughter chromosome
• C) synapsis
• D) tetrad
12
Quiz
• 11- During ______ , the sister chromatids are lined up at the equator.
• A) prophase I
• B) anaphase II
• C) metaphase I
• D) metaphase II
12- During ______ , the sister chromatids separate and move toward the poles.
• A) telophase II
• B) metaphase II
• C) anaphase I
• D) anaphase II
13
Quiz
• 13- Which of the following comparisons of mitosis versus meiosis is NOT
correct for animal cells?
• A) occurs in somatic cells<---->occurs in the gonads
• B) two daughter cells<---->four daughter cells
• C) diploid daughter cells<---->haploid daughter cells
• D) one cell division<---->two cell divisions
• E) homologous chromosomes pair up<---->homologous chromosomes do not
pair up
14