Life Cycle and Somatic Cell Cycle

Question 1

Name the five phases in M-phase?

Answer 1

1. prophase
2. preprometaphase
3. metaphase
4. anaphase
5. telophase
   or
6. interphase
7. prophase
8. metaphase
9. anaphase
10. telophase

Question 2

Name the five phases of the eukaryotic cell cycle.

Answer 2

G1 – First Growth (cell grows in size, as organelles duplicate)
S – Synthesis (replication of DNA, centrosome (centriole) replicated)
G2 – Second Growth (DNA is proof-read, enzymes for division are made)
M – Mitosis (DNA is redistributed and nucleus divides)
C – Cytokinesis (cell divides)

Question 3

What is the difference between a somatic cell and a gamete?

Answer 3

1. Somatic cells (diploid) arise from somatic cells
   a. Duplication occurs by cell cycle
   b. Makes exact copies (one 2n cell makes two identical 2n cells)
2. Gametes (haploid) arise from GERM cells
   a. Gametes generated by reductive cell division
   b. Reduces 2 sets of chromosomes to 1 and introduces genetic variation
   c. One 2n cell makes four n cells that are genetically different

Question 4

Explain the phases in the animal life cycle.

Answer 4

1. Reproduction (Meiosis and fertilization)
   a. The new cells have half the number of chromosomes (n) haploid (1 set of chromosomes – gamete – egg and sperm)
   b. Produces 4 genetically different cells, from the parent cell (One 2n cell makes four n cells)
   c. During fertilization gametes fuse to form a (2n) zygote – the first cell of life
2. Growth and Repair (Mitosis)
   a. Cells maintain the same number of chromosomes (2n) diploid (2 sets of chromosomes – somatic cells)
   b. Produces 2 identical cells from the parent cells

Question 5

Compare & contrast chromosome structure in prokaryotes and eukaryotes.

Answer 5

Prokaryotic chromosomes
- Double-stranded circular DNA
- Single chromosome (haploid – n)
- Short circular DNA molecules
- 1-5 um
Eukaryotic chromosomes
- Long strands of DNA
- Several chromosomes paired (diploid – 2n)
- Long linear DNA molecules
- 10-100 um

Question 6

Label the cell
http://timvandevall.com/wp-content/uploads/animal-cell-diagram-unlabled-1.png

Answer 6

https://timvandevall.com/wp-content/uploads/animal-cell-labeled-1.png

Question 7

Label the cell
https://www.sciencefacts.net/wp-content/uploads/2020/06/Label-the-Plant-Cell-Worksheet.jpg

Answer 7

https://www.sciencefacts.net/wp-content/uploads/2020/01/Plant-Cell-Diagram.jpg

Question 8

Label the cell
https://lh5.ggpht.com/-1FnQEhN7gi0/Uk_p-uavdXI/AAAAAAAACV4/uSdVc3w_jQg/image%25255B31%25255D.png?imgmax=800

Answer 8

1 Capsule
2 Cell wall
3 Plasma membrane
4 Cytoplasm
5 Mesosome
6 Pili (pilus = 1)
7 Circular DNA
8 Plasmid
9 Ribosomes
10 Flagellum

Question 9

What is the endosymbiotic theory?

Answer 9

• Explains the origins of eukaryotic cell.
• Organelles such as mitochondria in animals and fungi and chloroplasts in plants arose from phagocytosis of one bacterium by another
• ancestral prokaryote - infolding of pm - endosymbiosis - eukaryote

Question 10

What are the functions of the following structures?
Nucleus, Chromosomes, Nucleolus, Ribosomes, ER, Golgi apparatus, Vaculoles, Centrovacuole, Cell wall, Flagella & cilia, Chloroplasts, Lysosomes, Mitochondria, Cytoskeleton, Plasma membrane

Answer 10

Nucleus – stores genetic info
Chromosomes – allows DNA to be accurately copied during cell division
Nucleolus – facilitates ribosome biogenesis transfer RNA
Ribosomes – site protein synthesis in cell
ER – produces protein for rest of cell to function, samples and modifies proteins
Golgi apparatus – distribute proteins
Vaculoles – stores enzymes
Centrovacuole – stores H2O & nutrients
Cell wall – structure and protection
Flagella & cilia – movement
Chloroplasts – convert light E – bond E
Lysosomes – break down unused organelles, recycle molecules
Mitochondria – powerhouse of cell, generates ATP
Cytoskeleton – maintain shape inside cell
Plasma membrane – exchanges material with environment