Molecular Biology & Process of Reproduction

Question 1

DNA Replication- why, when, how?

Answer 1

DNA replication (conservative replication)- Before mitosis a copy of chromosomes are made so each cell has a complete set. Original DNA is replicated at end of interphase so 2 copies are present and distributed in mitosis. It’s called semi-conservative because each new chromosome is made of 1 old strand and 1 new strand.

Question 2

Mitosis

Answer 2

Cell Division

• reproduction-> offspring
• repair
• growth
• replacement/ wear & tear
• malignancy- cancer
• hypertrophy
• increased WBC when sick

Question 3

Chromosome # in mother cell; just before mitosis; in daughter cells; in meiotic cells

Answer 3

in mother cell- 23
- just before mitosis- 4n
- daughter cells- 46 (2n 1 from & 1 from dad)
??

Question 4

Meiosis.. why ?

Answer 4

necessary for sexual reproduction

• creates diversity by blending genes
• need to create haploid cells so in fertilization diploid organism results
• end result is production of sperm & egg
• prior to meiosis, DNA replication occurs

Question 5

Sources of diversity in offspring?

Answer 5

meiosis- blends genes

Question 6

Problems with reproduction

Answer 6

Mutations-> errors during transcription, translation, DNA replication or original DNA strand can be altered by change of base due to addition, deletion, reversal

Question 7

Synapsis

Answer 7

chromosomes come together and pieces break off + swap (happens in metaphase)

Question 8

Homologous

Answer 8

same chromosomal pair

Question 9

Non-disjunction

Answer 9

one cell gets 2 copies of a chromosome + 1 will get none and will most likely die. Results in down syndrome (trisomy)

Question 10

Transcribe DNA to RNA: ACCGTT

Answer 10

UGGCAA
- process is catalyzed by RNA polymerase
Finished M-RNA leaves the nucleus and goes to ribosomes on RER or in cytoplasm

Question 11

Conversion of RNA into Protein

Answer 11

• MRNA- connects to ribosome
• codons each code for a specific amino acid
• ribosomes read M-RNA and assemble into polypeptide
• TRNA carries A. A to ribosome
• anticodon on trna matches coon on mrna so correct amino acid is added to growing strand

Question 12

Chromosomes- how are male and female difference

Answer 12

male- XY

female- XX

Question 13

DNA vs RNA

Answer 13

Similarities: 5 carbon sugar, phosphate groups, AGC, polymers of nucleotides

DNA
Pentose= deoxyribose
A bonds with T
double helix
only in nucleus
only 1 type

RNA
Pentose= Ribose
A bonds with U
Single Helix
In nucleus or cytoplasm
3 types: MRNA TRNA RRNA