Chapter 4: Genes and Cellular Function

Question 1

DNA Function and Structure:

Answer 1

Long threadlike diameter of 2 nm. 46 molecules o DNA, 2 m in length.
A-T, G-C= Base Pairs. DNA carries genes for synthesis of proteins.
3 DNA nucleotide for one amino acid is base triplet. (mRNA=codon)

Question 2

Chromatin and Chromosomes:

Answer 2

DNA comprised of chromatin, occurring as 46 filaments as chromosomes.
Sister Chromatids: exact replica of each other when cell is dividing.

Question 3

Genetic Code

Answer 3

Uses A,C,G,T to code for amino acid sequence of proteins.

Question 4

Messenger RNA:

Answer 4

Made when a gene is activated. Transcription is copying DNA to RNA. RNA polymerase binds to DNA and assembles RNA, opens up helix of DNA and makes corrosponding bases. C=G, A=U.

Question 5

Translation: converts language of nucleotides into language of amino acids.

Answer 5

converts language of nucleotides into language of amino acids.
Carried out by:
mRNA
tRNA
Ribosomes
3 steps:
Initiation
Elongation
Termination

Question 6

Protein Processing and Secretion

Answer 6

1. Protein threads through ER membrane pore and into cistern. Enzymes modify protein (postranslational modification)
2. RER pinches off transport vesicles with clathrin to carry proteins to Golgi Complex.
3. Golgi fuses proteins to form new Golgi cis3 cistern.
4. Cis3 travels through golgi to opposite face, producing new enzymes.
5. Trans4 cistern (farthest away from ER) breaks into Golgi vesicles.

Question 7

Cell Cycle: G,S,G,M

Answer 7

G: first gap phase, cell synthesizes proteins, grows, and carries out task for bodies.
S: synthesis phase: cell makes duplicate copy of centrioles and DNA.
g2: Second Gap Phase: interval between DNA replication and cell division. Cell grows, makes organelles, finishes replicating centrioles, synthesizes enzymes.
M: Mitotic Phase: cell replicates nucleus and forms daughter cells.

Question 8

Mitosis:

Answer 8

Cell division: 
-development of an individual from an egg,, growth of all tissues and organs, replacement of cells that die, repair damaged tissues
4 Phases of Mitosis:
Prophase
Metaphase
Anaphase
Telophase

Question 9

Karyotype

Answer 9

Chart of 46 normal human chromosomes.
Each pair called homologous chromosome.
Sex Chromosomes: X AND Y
All others are autosomes.