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Bio 121N Exam 4 Review > Exam 4 Review > Flashcards

Exam 4 Review Flashcards

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1
Q

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

A

Translation

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2
Q

Where does Translation occur in eukaryotic cells?

A

Cytosol and mitochondrion (Chloroplast in plants)

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3
Q

Which two subunits form prokaryotic ribosomes?

A

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

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4
Q

Which two subunits form eukaryotic ribosomes?

A

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

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5
Q

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

A

Ribosomal proteins and rRNA (Ribosomal RNA)

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6
Q

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

A

Codons

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7
Q

Describe the first stage of translation (Initiation).

A

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.

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8
Q

Describe the second stage of translation (Elongation).

A

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.

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9
Q

Describe the third stage of translation (Termination).

A

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.

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10
Q

What energy source drives each stage in translation?

A

GTP

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11
Q

Which specialized proteins are required in translation?

A

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

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12
Q

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

A

tRNA (Transfer RNA)

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13
Q

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

A

Aminoacyl-tRNA Synthetase

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14
Q

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

A

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) .

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15
Q

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

A

Peptidyl Transferase

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16
Q

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

A

RNA molecule (Ribozyme)

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17
Q

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

A

Aminoacyl-tRNA Synthetase

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18
Q

Which PROTEIN is required to end translation?

A

Release factor(s)

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19
Q

What CODON is required to end translation?

A

Stop codon(s)

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20
Q

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

A

Stop codon

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21
Q

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

A

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

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22
Q

Where do chemical modification to mRNA occur in eukaryotic cells?

A

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

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23
Q

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

A

Capping Enzyme complex

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24
Q

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

A

Polyadenylate polymerase

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25
Q

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

A

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

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26
Q

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

A

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

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27
Q

Which enzyme complex splices new mRNA molecules?

A

Spliceosome(s)

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28
Q

What types of biological molecules and structures form spliceosomes?

A

SNURPS (Small nuclear Ribonucleoproteins that contain proteins and RNA)

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29
Q

The nucleotide sequences removed from mRNA during splicing are called-

A

Introns

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30
Q

The nucleotide sequences remaining in mRNA after splicing are called-

A

Exons

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31
Q

Are mRNA molecules shorter before or after splicing?

A

After

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32
Q

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

A

Exons

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33
Q

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

A

Ribozymes

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34
Q

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

A

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

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35
Q

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

A

It magnifies the coding power of the human genome.

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36
Q

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

A

Yes

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37
Q

What type of abnormal mRNA process causes Beta-Thalassemia?

A

Splicing that causes the absence of beta globin synthesis.

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38
Q

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

A

Yes

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39
Q

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

A

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

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40
Q

How does fertilization restore the diploid number in children?

A

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

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41
Q

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

A

Meiotic cell division

42
Q

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

A

Meiotic cell division

43
Q

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

A

Meiotic cell divison

44
Q

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

A

Meiotic cell division

45
Q

Why does meiotic cell division require two cell division events?

A

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

46
Q

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

A

Four

47
Q

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

A

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

48
Q

What is the fate of most aneuploid gametes?

A

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

49
Q

Are the cells of most miscarried fetuses aneuploid?

A

Yes

50
Q

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

A

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

51
Q

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

A

Yes

52
Q

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?

A

Crossing over

53
Q

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

A

Yes

54
Q

Why is genetic variation beneficial for populations?

A

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

55
Q

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

A

Rats

56
Q

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

A

Rats

57
Q

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

A

Yeast

58
Q

Define Allele-

A

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

59
Q

Define locus-

A

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.

60
Q

Define homozygote-

A

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

61
Q

Define heterozygous-

A

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

62
Q

Define Dominant phenotype-

A

A genetic instructions expressed in a phenotype.

63
Q

Define Recessive phenotype-

A

Instructions that are NOT expressed in a phenotype.

64
Q

Define True-Breeding -

A

A trait that remains constant over multiple generations.

65
Q

Why do alleles contain different genetic information?

A

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

66
Q

What is an individual’s genotype?

A

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

67
Q

What is an individual’s phenotype?

A

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

68
Q

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

A

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

69
Q

What factors interact to form a phenotype?

A

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

70
Q

What types of environmental factors affect phenotype?

A

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

71
Q

What types of environmental factors can affect behavioral phenotypes?

A

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

72
Q

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

A

Yes

73
Q

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

A

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

74
Q

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

A

XX chromosomes for females and XY chromosomes for males.

75
Q

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

A

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

76
Q

What came out of Mendel’s monohybrid experiment?

A

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).

77
Q

Why did Mendel replicate each monohybrid crossing experiment many times?

A

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

78
Q

What principles of Inheritance emerged from Mendel’s experiments?

A

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).

79
Q

Describe the purpose of testcross

A

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

80
Q

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

A

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.

81
Q

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

A

1 allele comes from each parent.

82
Q

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

A

No

83
Q

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

A

One

84
Q

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

A

Alleles only regulate a specific trait.

85
Q

Is achondroplasia (dwarfism) recessive or dominant?

A

Dominant

86
Q

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

A

Fathers can have a mutated “A” allele that combines with the mother’s “a” allele causing an Aa genotype.

87
Q

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

A

The genotype is lethal.

88
Q

What is incomplete dominance in heterozygotes?

A

When the different alleles are both partially expressed.

89
Q

What is co-dominance in heterozygotes?

A

When the different alleles are both fully expressed.

90
Q

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

A

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

91
Q

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

A

Mitochondrion genome

92
Q

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

A

Mitochondrion and chloroplasts.

93
Q

Why are some genetic disorders inherited only from the female?

A

Cytoplasmic inheritance

94
Q

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

A

It only occurs in the egg’s mitochondria.

95
Q

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

A

Chloroplast

96
Q

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

A

Mitochondrion

97
Q

Why is the allele for sickle cell “pleiotropic”?

A

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.

98
Q

What is polygenic inheritance? What are some examples?

A

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

99
Q

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

A

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.

100
Q

Why do males have more X-linked recessive disorders?

A

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

101
Q

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

A

Dominant

102
Q

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

A

Mutations and gene duplication

Bio 121N Exam 4 Review (1 decks)

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