Exam 4

Question 1

What is a gene and give an example?

Answer 1

Functional piece of DNA for a speci trait/Sequence of nucleotides on a chromosome
Example: eye color

Question 2

What is an allele and give an example?

Answer 2

subype of the trait
Example: B or b

Question 3

What is dominant?

Answer 3

(B)
Allele that is always expressed
Homozygous or heterozygous and its always written first in genotype

Question 4

What is recessive?

Answer 4

(b)
Must be homozygous to be expressed
Always written second in genotype.

Question 5

What is the genotype?

Answer 5

Refers to the alleles present (bb)

Question 6

What is a phenotype?

Answer 6

Physical expression of allele (example blue eyes)

Question 7

What is homozygous and heterozygous?

Answer 7

Homo- having two identical alleles for a particular genes (bb or BB)
Hetero- acing 1 different alleles of a particular gene (Bb)

Question 8

What is the law of independent assortment?

Answer 8

How the chromosomes line up at metaphase 1.
Chromosomes sort to one side or the other without regard to the others.

Question 9

What is the law of segragation?

Answer 9

How chromosomes are separated to different poles in Anaphase 1
Homologous chromosomes separate and Goes into different cells

Question 10

What is the law of segregation?

Answer 10

The two copies of each genetic factor segregates to ensure that each parents offspring attains one factor.

Question 11

What is non-Mendelian inheritance?

Answer 11

Codominance: both dominant and neither is recessive to the other when together
Polygenic: many genes involved in phenotype

Question 12

How is sex determines in humans?

Answer 12

The reserve of a Y chromosome
2X chromosomes= female
Having a Y chromosome (XY)= male

Question 13

How many chromosomes does humans have?

Answer 13

46 total
1 pair of sex chromosomes
22 pairs of autosomes

Question 14

What is dosage compensation mechanisms?

Answer 14

1. Up regulation
2. Down regulation
   3.inactiviation of one of the two x chromosomes

Question 15

What are polymerases?

Answer 15

Enzymes that synthesizes chains of nuclei acids

Question 16

What are the 2 types of polymerase?

Answer 16

DNA polymerase-
RNA polymerase AKA dna primase- synthesizes rna primers

Question 17

What is the role of helicase?

Answer 17

Unwinds the double helix

Question 18

What is the role of DNA ligase?

Answer 18

Joins the ends of DNA and repair

Question 19

What’s the role of single strand binding protein?

Answer 19

Stabilizes single strained regions

Question 20

What’s the role of DNA polymerase I AND III

Answer 20

DNA polymerase I- erases primer and fills gaps
DNA polymerase III- synthesizes DNA and repair

Question 21

What is the structure of DNA?

Answer 21

Nucleic acid composed of nucleotides
5 carbon sugar called deoxyribose
Has a nitrogenous base

Question 22

What is phosphodiester bond

Answer 22

Formed between phosphate groups of one nucleotide and the 3’ -OH of the other nucleotide

Question 23

What did Rosalind Franklin do

Answer 23

In 1951-1953 she discovered that DNA is helical

Question 24

What are the complimentary base pairs?

Answer 24

Guanine(G) forms with Cytosine(C)
Adenine(A)forms with Thymines(T)

Question 25

What does DNA replication require?

Answer 25

1.Template- something to copy 2. Enzymes- something to do the copying 3.Nucleotides- building blocks to make copy

Question 26

What are the stages of DNA replication?

Answer 26

1.Initiation- replication begins 2. Elongation- news strands of dna are synthesized 3. Termination- replication is terminated

Question 27

How does replication take places in prokaryotic

Answer 27

Replication begins at the origin of replication Single circular molecule of dna

Question 28

What does the 3 dna polymerase do

Answer 28

DNA polymerase I- removes primers and replaces with dna DNA polymerase II- dna repair DNA polymerase III- adds nucleotides

Question 29

What enzymes prevent super coiling?

Answer 29

Topoisomerase

Question 30

What does leading and lagging strand do?

Answer 30

Leading- synthesized continuously from an initial primer Lagging- synthesized discontinuously with multiple priming events

Question 31

What are Okazaki fragments?

Answer 31

DNA fragments that are produced on the lagging strand

Question 32

What are telomeres?

Answer 32

The end cap to protect chromosomes

Question 33

What is transcription and translation

Answer 33

Translation-new proteins are made RNA to amino acids Transcription-the process where dna sequence is copied DNA TO RNA

Question 34

What must be present in the cytoplasm for translation to happen?

Answer 34

mRNA Free amino acids Ribosomal units Transfer RNA

Question 35

What is a codon?

Answer 35

A sequence of three nucelotides in DNa or RNA that codes for a specific amino acid

Question 36

Which ends are nucelotides added?

Answer 36

3’ prime end

Question 37

What does DNa polymerase need to function?

Answer 37

Primers

Question 38

Where did mitochondria and DNA come from?

Answer 38

They were engulfed and came from bacteria Bacteria was engulfed by eukaryotic cells

Question 39

What is plasmid?

Answer 39

Tiny pieces of dna

Question 40

What does bacteria use plasmid for?

Answer 40

For resistence Bacteria can gets genes from each other

Question 41

Why is supercooling bad?

Answer 41

Disrupts transcription and replication by making DNA strands too tightly wound

Question 42

What direction does replication take place?

Answer 42

5’ to 3’

Question 43

What does a stop codon do?

Answer 43

Signals the end f protein synthesis in a cell

Question 44

What does release factor do?

Answer 44

Crucial for initiating the release of the polypeptide chain during termination of protein sysnthesis

Question 45

What is a triplet in RNA AND DNA?

Answer 45

CODON

Question 46

What is a triplet in TRNA?

Answer 46

ANTCODON