Exam 4 Review

Question 1

Which process converts a mRNA’s sequence information into a protein with a specific amino acid sequence?

Answer 1

Translation

Question 2

Where does Translation occur in eukaryotic cells?

Answer 2

Cytosol and mitochondrion (Chloroplast in plants)

Question 3

Which two subunits form prokaryotic ribosomes?

Answer 3

1 large 50 S and 1 small 30 S (S is Svedberg, a unit of particle size)

Question 4

Which two subunits form eukaryotic ribosomes?

Answer 4

1 large 60 S and 1 small 40 S (S is Svedberg, a unit of particle size)

Question 5

Which two types of biological molecules interact in order to form ribosomal subunits?

Answer 5

Ribosomal proteins and rRNA (Ribosomal RNA)

Question 6

What genetic code words (in mRNA) determines a protein’s amino acid sequence?

Answer 6

Codons

Question 7

Describe the first stage of translation (Initiation).

Answer 7

A small ribosomal subunit binds to the 5’ end cap, then tRNA binds to the start codon after recognizing it.
The tRNA also delivers methionine which is the first amino acid every ribosome synthesizes.
The large ribosomal subunit then binds and forms the Translation Initiation Complex that allows translation to begin at the start codon.

Question 8

Describe the second stage of translation (Elongation).

Answer 8

The ribosome reads the codon sequence in mRNA to synthesize the protein. This process requires GTP, an energy-rich molecule.
The large ribosomal subunit contains an enzyme that links amino acids together at ~ 3-10 reactions per second.

Question 9

Describe the third stage of translation (Termination).

Answer 9

The ribosome meets the stop codon, which pauses ribosomal activity.
A protein (the release factor) enters the ribosome and interacts with the stop codon to detach the mRNA and subunits, along with releasing the subunits, mRNA, and new protein.

Question 10

What energy source drives each stage in translation?

Answer 10

GTP

Question 11

Which specialized proteins are required in translation?

Answer 11

Helicase in the initiation phase,
peptidyl Transferase in the elongation phase,
and the release factor protein in the termination phase.

Question 12

What specialized RNA type delivers amino acids to ribosomes during translation?

Answer 12

tRNA (Transfer RNA)

Question 13

Which enzyme(s) link proper amino acids to the proper tRNA?

Answer 13

Aminoacyl-tRNA Synthetase

Question 14

How does the proper tRNA recognize the proper codon in mRNA?

Answer 14

Through codon and anticodon base pairings. It aligns in an antiparallel orientation (the codon and anticodon are opposite 5’-3’ orientation to interact via Complementary Base Pairing) .

Question 15

What enzyme in the large ribosomal subunit links amino acids together during the elongation phase?

Answer 15

Peptidyl Transferase

Question 16

Is Peptidyl Transferase a protein or RNA molecule (Ribozyme)?

Answer 16

RNA molecule (Ribozyme)

Question 17

Which protein proofreads the tRNAs before they enter the Ribosome during elongation?

Answer 17

Aminoacyl-tRNA Synthetase

Question 18

Which PROTEIN is required to end translation?

Answer 18

Release factor(s)

Question 19

What CODON is required to end translation?

Answer 19

Stop codon(s)

Question 20

What codon does the release factor recognize in the transcript (mRNA)?

Answer 20

Stop codon

Question 21

What types of antibiotics kill bacteria by inhibiting Ribosomal activity/preventing protein synthesis?

Answer 21

Macrolide, Chloramphenicol, Erythromycin, Tetracyclines, streptomycin, clindamycin, and linezolid antibiotics

Question 22

Where do chemical modification to mRNA occur in eukaryotic cells?

Answer 22

The nucleus to ensure various factors of the mRNA are kept/stable

Question 23

Which enzyme adds the 5’ G-cap to mRNA?

Answer 23

Capping Enzyme complex

Question 24

Which enzyme adds the 3’ poly-A tail to mRNA?

Answer 24

Polyadenylate polymerase

Question 25

What are the three functions of the 5' end cap/ 3' poly-A tail?

Answer 25

Increase stability, enable transportation, and enable interaction between mRNA and ribosomes in the cytoplasm

Question 26

Why do some human viruses attach end caps/poly-A tails to their mRNAs?

Answer 26

To prevent destruction of the RNase Enzymes. Also allows for immune system suppression while allowing their translation to occur in Human Ribosomes to "reproduce".

Question 27

Which enzyme complex splices new mRNA molecules?

Answer 27

Spliceosome(s)

Question 28

What types of biological molecules and structures form spliceosomes?

Answer 28

SNURPS (Small nuclear Ribonucleoproteins that contain proteins and RNA)

Question 29

The nucleotide sequences removed from mRNA during splicing are called-

Answer 29

Introns

Question 30

The nucleotide sequences remaining in mRNA after splicing are called-

Answer 30

Exons

Question 31

Are mRNA molecules shorter before or after splicing?

Answer 31

After

Question 32

Which sequences in mature mRNA determine the amino acid sequence of a protein?

Answer 32

Exons

Question 33

Some introns have the catalytic ability to splice themselves out of mRNA. RNA enzymes are called-

Answer 33

Ribozymes

Question 34

How does alternative splicing enable cells to produce multiple versions of a protein from a single gene?

Answer 34

Multiple mRNA with different exons or different nucleotide sequences. Specialized versions of a protein with different amino acid sequences and different functions

Question 35

What is the benefit of producing multiple versions of a protein from one gene?

Answer 35

It magnifies the coding power of the human genome.

Question 36

Does alternative splicing result in different combinations of exons in the spliced mRNAs?

Answer 36

Yes

Question 37

What type of abnormal mRNA process causes Beta-Thalassemia?

Answer 37

Splicing that causes the absence of beta globin synthesis.

Question 38

Does abnormal splicing result in oncoproteins to increase the risk of cancer?

Answer 38

Yes

Question 39

Where does meiotic cell division occur in- Women? Men? Flowers?

Answer 39

Ovaries in women, testes in men, and the ovule and pistil (female) / anthers and stamen (male) in flowers.

Question 40

How does fertilization restore the diploid number in children?

Answer 40

2 haploid cells (1 from each parent) are combined to create the zygote with two sets of chromosomes (46).

Question 41

What type of cell division is necessary to- Form a haploid gamete? Produce offspring that is genetically distinct from the parent(s)?

Answer 41

Meiotic cell division

Question 42

Which type of cell division is necessary to- Maintain a constant number of chromosomes in the nucleus across generations?

Answer 42

Meiotic cell division

Question 43

Which type of cell division is necessary to produce genetically variable haploid gametes from diploid germ-line cells?

Answer 43

Meiotic cell divison

Question 44

Which type of cell division is necessary to enable sexual reproduction?

Answer 44

Meiotic cell division

Question 45

Why does meiotic cell division require two cell division events?

Answer 45

To produce 4 haploid cells that can develop into haploid gametes.

Question 46

How many haploid cells are produced from one germ-line cell after Meiosis 2?

Answer 46

Four

Question 47

How does nondisjunction during meiosis 1 and 2 result in genetic disorders?

Answer 47

It produces aneuploid cells that have an abnormal number of chromosomes in the nucleus.

Question 48

What is the fate of most aneuploid gametes?

Answer 48

Self destruction via apoptosis. A small percentage of these gametes survive and cause birth defects, increased risk of cancer, or an increased aging rate.

Question 49

Are the cells of most miscarried fetuses aneuploid?

Answer 49

Yes

Question 50

During which part of meiosis 1/meiosis 2 does the spindle separate the- Homologous chromosome pairs? Sister chromatid pairs?

Answer 50

During Anaphase 1 in Meiosis 1 for the homologous pairs. During Anaphase 2 of Meiosis 2 for the sister chromatids.

Question 51

Can your genome contain chromosomes from each of your 4 grandparents?

Answer 51

Yes

Question 52

Which process forms new allele combinations on each homologous chromosomes in prophase 1 of meiosis 1 and results in a recombinant of chromosomes from both your parents?

Answer 52

Crossing over

Question 53

Does each gamete you produce have an equal probability of containing any of the possible combination of your Maternal/Paternal chromosomes?

Answer 53

Yes

Question 54

Why is genetic variation beneficial for populations?

Answer 54

It increases reproduction in the current environment for long term survival.

Question 55

Which model system would you select to facilitate the investigation of the human brain?

Answer 55

Rats

Question 56

Which model system would you select to facilitate the investigation of the human immune system?

Answer 56

Rats

Question 57

Which model system would you select to facilitate the investigation of the cellular processes that increase crop yield?

Answer 57

Yeast

Question 58

Define Allele-

Answer 58

Different forms of a single gene with unique nucleotide sequences. Contains different genetic information and formed by mutations in existing ones.

Question 59

Define locus-

Answer 59

The "unit of heredity" at a specific site on the chromosome that regulates a trait. It contains 1+ genes that regulate the trait and regulatory nucleotide sequences that control gene expression.

Question 60

Define homozygote-

Answer 60

A gene with two copies of the same allele (dominant or recessive).

Question 61

Define heterozygous-

Answer 61

A gene with two different alleles (one dominant, one recessive).

Question 62

Define Dominant phenotype-

Answer 62

A genetic instructions expressed in a phenotype.

Question 63

Define Recessive phenotype-

Answer 63

Instructions that are NOT expressed in a phenotype.

Question 64

Define True-Breeding -

Answer 64

A trait that remains constant over multiple generations.

Question 65

Why do alleles contain different genetic information?

Answer 65

It contributes to phenotypes, shaping how traits can evolve overtime.

Question 66

What is an individual's genotype?

Answer 66

The two alleles that a diploid individual has for a gene.

Question 67

What is an individual's phenotype?

Answer 67

The physical traits/behaviors of a person that is observable or measurable.

Question 68

What genotype in two parents always relates to true-breeding? Why?

Answer 68

Homozygous genotypes, as it ensures all gametes contain an identical allele.

Question 69

What factors interact to form a phenotype?

Answer 69

The product of complex interactions between the genotype and unique environmental conditions.

Question 70

What types of environmental factors affect phenotype?

Answer 70

Disease, nutrition, physical activity, sensory stimulation, social interactions, and weather.

Question 71

What types of environmental factors can affect behavioral phenotypes?

Answer 71

Parental care, gestation in the womb (cows), and nutrition difference.

Question 72

Does a pregnant mother's environmental conditions affect the phenotype of her developing child?

Answer 72

Yes

Question 73

What are autosomes? What is the largest and what is the smallest?

Answer 73

Chromosomes 1-22. 1 is the largest and 22 is the smallest.

Question 74

What sex chromosome combination enables a female child to develop? a male child?

Answer 74

XX chromosomes for females and XY chromosomes for males.

Question 75

Why does the sex chromosome in the male gamete determine a child's gender?

Answer 75

The egg always contains an X chromosome while the sperm can contain an X or a Y chromosome.

Question 76

What came out of Mendel's monohybrid experiment?

Answer 76

He determined a ratio of the F2 generation for traits with 3 dominant, 1 recessive that resulted in: 1 dominant, 2 heterozygous, and 1 recessive (1:2:1 Ratio).

Question 77

Why did Mendel replicate each monohybrid crossing experiment many times?

Answer 77

To avoid publicizing a misleading result, increase pattern detection, and generate multiple data points for mathematical evaluation.

Question 78

What principles of Inheritance emerged from Mendel's experiments?

Answer 78

Different traits of parents DON'T mix with offspring, F1 offspring do NOT show different trait combinations, Diploid individuals have two alleles for each gene (inherited from each parent).

Question 79

Describe the purpose of testcross

Answer 79

To determine the alleles of an unknown genotype (by crossing with a homo-recessive).

Question 80

What result shows that the individual is heterozygous? homo-dominant?

Answer 80

If the result contains both homo-dominant and homo-recessive offspring, the genotype is heterozygous. If the result contains heterozygous (all dominant present), then it is homo-dominant.

Question 81

Why are there two alleles in the nucleus of a gene in autosomes?

Answer 81

1 allele comes from each parent.

Question 82

Do males have two copies of the genes on the X and Y chromosome?

Answer 82

No

Question 83

According to Mendel's law of segregation, do one or both alleles of a gene enter each gamete during meiotic cell division?

Answer 83

One

Question 84

Why don't different traits of parents mix in the offspring?

Answer 84

Alleles only regulate a specific trait.

Question 85

Is achondroplasia (dwarfism) recessive or dominant?

Answer 85

Dominant

Question 86

How can wild-type parents have a child with achondroplasia?

Answer 86

Fathers can have a mutated "A" allele that combines with the mother's "a" allele causing an Aa genotype.

Question 87

Why is no one homo-dominant (AA) for achondroplasia?

Answer 87

The genotype is lethal.

Question 88

What is incomplete dominance in heterozygotes?

Answer 88

When the different alleles are both partially expressed.

Question 89

What is co-dominance in heterozygotes?

Answer 89

When the different alleles are both fully expressed.

Question 90

Why do safe blood transfusions require a knowledge on co-dominance between the "A" and "B" alleles of the ABO gene?

Answer 90

Incompatible blood will result in a destructive auto-immune response.

Question 91

What organelle(s) provide the basis of cytoplasmic inheritance in humans?

Answer 91

Mitochondrion genome

Question 92

What organelle(s) provide the basis of cytoplasmic inheritance in plants?

Answer 92

Mitochondrion and chloroplasts.

Question 93

Why are some genetic disorders inherited only from the female?

Answer 93

Cytoplasmic inheritance

Question 94

Why are traits inherited via cytoplasmic inheritance only from the female?

Answer 94

It only occurs in the egg's mitochondria.

Question 95

If a new mutation doesn't occur in the nucleus or mitochondrion, which organelle does the mutation occur?

Answer 95

Chloroplast

Question 96

If a new mutation doesn't occur in the nucleus, which organelle does this mutation occur?

Answer 96

Mitochondrion

Question 97

Why is the allele for sickle cell "pleiotropic"?

Answer 97

It affects the beta globin shape circulation, hemoglobin shape, oxygen, RBC shape, infection, bone tissue injury, pain, and paralysis. It is the ability of a gene to influence many aspects of one's phenotype.

Question 98

What is polygenic inheritance? What are some examples?

Answer 98

The regulation of one trait via many genes. Examples include body shape, behavior, height, weight, eye/hair color, etc.

Question 99

How do melanocytes determine skin tone/eye color/hair color?

Answer 99

They make pigments that affect colors. The two types of pigments are eumelanin and pheomelanin. The number of cells and their organelles also affect colors.

Question 100

Why do males have more X-linked recessive disorders?

Answer 100

They do not have a second copy of the X chromosome that carries a dominant allele.

Question 101

Is a recessive mutation on the X chromosome expressed as a dominant or recessive phenotype in males?

Answer 101

Dominant

Question 102

What are the two sources of new alleles in a population?

Answer 102

Mutations and gene duplication