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Worksheets

sinh

Total questions: 121

Worksheet time: 61hrs 30mins

Name
Class
Date
1.

The set of four bases in DNA is denoted as which group?

a)

A, U, G, C

b)

A, T, G, C

c)

A, U, G, T

d)

U, T, G, A

2.

To distinguish structural genes from regulatory genes, the classification is based on what?

a)

The function of the gene product

b)

The phenotype expressed

c)

The mode of gene interaction

d)

Gene structure

3.

Which region of a gene determines the amino acid sequence of the encoded protein?

a)

Operator region

b)

Coding region

c)

Regulatory region

d)

Terminator region

4.

The specific anticodon belongs to which type of RNA?

a)

mRNA

b)

DNA

c)

tRNA

d)

rRNA

5.

In eukaryotes, the nucleotide sequences within a gene that actually code for amino acids are called what?

a)

Introns

b)

Fragmented gene

c)

Operator region

d)

Exons

6.

Which sequence correctly represents the flow of genetic information at the molecular level?

a)

Gene → mRNA → Polypeptide → Protein

b)

mRNA → Gene → Polypeptide → Protein

c)

Gene → Polypeptide → mRNA → Protein

d)

Gene → Polypeptide → mRNA → Protein

7.

During translation, the first peptide bond is formed between which two components?

a)

The initiator amino acid and the next (first elongating) amino acid

b)

Any two adjacent amino acids

c)

The initiator amino acid and the second elongating amino acid only

d)

Two random amino acids

8.

The fact that the codon 5' AUG 3' specifies methionine in eukaryotes demonstrates which property of the genetic code?

a)

Degeneracy

b)

Specificity

c)

Universality

d)

Ambiguity

9.

The primary enzyme that participates in transcription is which of the following?

a)

RNA polymerase

b)

DNA polymerase

c)

DNA ligase

d)

Restriction endonuclease

10.

During transcription, the newly synthesized polynucleotide chain is elongated in which direction?

a)

5' → 3'

b)

5' → 5'

c)

3' → 5'

d)

3' → 3'

11.

Base-pairing in transcription follows which complementarity rule (DNA template to RNA)?

a)

A pairs with T; T pairs with A; G pairs with C; C pairs with G

b)

A pairs with U; T pairs with A; G pairs with C; C pairs with G

c)

A pairs with U; U pairs with A; G pairs with G; C pairs with C

d)

A pairs with A; T pairs with U; G pairs with C; C pairs with G

12.

Which nucleic acid acts as the “interpreter” or adapter during translation?

a)

DNA

b)

tRNA

c)

rRNA

d)

mRNA

13.

Which molecule is not directly involved as a component in translation?

a)

DNA

b)

rRNA

c)

Protein

d)

tRNA

14.

Which of the following participates in transcription?

a)

tRNA molecules

b)

Polypeptide chains

c)

DNA molecule

d)

Cellulose

15.

Which is not a function of DNA?

a)

Storage and preservation of genetic information

b)

Transmission of genetic information

c)

Expression of genetic information

d)

Direct manifestation of an organism’s traits

16.

mRNA carries which function?

a)

Acts as a template during translation

b)

Acts as a template during transcription

c)

Acts as a template during replication

d)

Acts as a template during reverse transcription

17.

In transcription, RNA polymerase moves along the template strand in which direction while synthesizing RNA?

a)

Always 5' → 3'

b)

Always 3' → 5'

c)

Sometimes 5' → 3', sometimes 3' → 5'

d)

Direction depends on gene length

18.

A tRNA region that pairs with codons on mRNA and has a 3′ end for amino acid attachment is called what?

a)

DNA

b)

mRNA

c)

rRNA

d)

tRNA anticodon loop

19.

The part of tRNA that can bind to protein to form a ribosome is which of the following?

a)

rRNA

b)

tRNA

c)

DNA

d)

mRNA

20.

An amino acid can be encoded by more than one codon. This demonstrates which property of the genetic code?

a)

Polarity

b)

Degeneracy

c)

Specificity

d)

Variability

21.

Which triplet is not a stop codon in translation (in the nucleus of eukaryotes)?

a)

UAA

b)

UGG

c)

UGA

d)

UAG

22.

Which triplet is the universal start codon for translation initiation?

a)

5' UGA 3'

b)

5' UAG 3'

c)

5' AUG 3'

d)

5' AGU 3'

23.

Regardless of species, all organisms use the same set of genetic code words for which property of the genetic code?

a)

Polarity

b)

Universality

c)

Variability

d)

Degeneracy

24.

Which component is not part of a mature eukaryotic mRNA involved in translation?

a)

DNA

b)

mRNA

c)

tRNA

d)

rRNA

25.

During translation, amino acids are activated and attached to tRNA by which molecules?

a)

mRNA

b)

rRNA

c)

tRNA

d)

Aminoacyl-tRNA synthetases

26.

Polyribosomes (polysomes) are linked by what during active translation?

a)

mRNA

b)

tRNA

c)

rRNA

d)

DNA

27.

In bacteria, translation can be coupled to transcription because ribosomes attach to which molecule as it is being transcribed?

a)

rRNA

b)

tRNA

c)

mRNA

d)

DNA

28.

Among the 64 codons in the genetic code, how many are stop codons?

a)

0

b)

2

c)

3

d)

4

29.

Which of the following best describes gene expression?

a)

Replication and transcription only

b)

Replication, transcription, and translation

c)

Replication, translation, and reverse transcription

d)

Transcription and translation

30.

Which level of genetic information transfer does not include replication?

a)

Transformation

b)

Translation

c)

Transcription

d)

Reverse transcription

31.

Which component is used as a template when measuring hydrogen-bond numbers between bases?

a)

Nucleotide composition

b)

Number of hydrogen bonds between bases

c)

Spatial structure of DNA

d)

Nucleotide sequence of DNA

32.

A gene specifies a product type as regulated by the nucleotide sequence of DNA. Which best describes that product type?

a)

A segment of DNA or RNA; polypeptide

b)

A segment of DNA; polypeptide only

c)

Any DNA or RNA; polypeptide only

d)

Whole DNA molecule; RNA or polypeptide

33.

During transcription, RNA polymerase uses which DNA strand orientation as it moves along the template?

a)

3' → 5' of DNA template; RNA synthesized 5' → 3'

b)

5' → 3' of DNA template; RNA synthesized 3' → 5'

c)

3' → 3' of DNA template; RNA synthesized 5' → 5'

d)

Direction is random

34.

The genetic code has the following distinctive feature regarding codon meaning:

a)

One codon can code for multiple amino acids

b)

Each codon codes for exactly one amino acid

c)

Each amino acid can be coded by multiple codons

d)

No codon specifies an amino acid

35.

A DNA segment that carries information to determine the amino acid sequence of a polypeptide or the sequence in tRNA is called what?

a)

Gene

b)

Amino acid

c)

Protein

d)

Nucleotide

36.

Synthesis of complementary DNA (cDNA) from an RNA template catalyzed by reverse transcriptase is called what?

a)

Replication

b)

Translation

c)

Reverse transcription

d)

Reverse replication

37.

Which statement is not correct when considering the process of translation?

a)

The codon set does not specify amino acids for stop codons

b)

The genetic code is read in triplets without overlap

c)

Amino acids in the polypeptide are linked by hydrogen bonds

d)

Ribosomes move along mRNA in the 5' → 3' direction

38.

Which statement best characterizes both DNA replication and transcription in organisms?

a)

Both involve the same template and product

b)

Both occur strictly according to the principle of complementarity

c)

Both require only DNA polymerase

d)

Both occur only in genes

39.

What species is commonly used as a model organism in gene and genome studies depicted in the worksheet diagram?

a)

Pea plant

b)

E. coli

c)

Fungus

d)

Fruit fly

40.

Which of the following correctly lists events in bacterial DNA replication?

a)

DNA polymerase moves along DNA 5' → 3'; leading and lagging strands synthesized; Okazaki fragments joined

b)

DNA polymerase moves 3' → 5'; lagging strand only is synthesized; Okazaki fragments degraded

c)

Ribosomes assemble at origins; Okazaki fragments initiate replication; helicase acts last

d)

DNA ligase synthesizes both strands; primase is unnecessary; no Okazaki fragments form

41.

During DNA replication, which of the following is the correct order of steps?

a)

Primase lays RNA primer; DNA polymerase extends; Okazaki fragments formed; ligase seals nicks

b)

DNA polymerase initiates; ligase extends; primase finishes; helicase unwinds last

c)

Ligase starts; Okazaki fragments deposited by helicase; primase unwinds DNA

d)

Helicase unwinds after synthesis; no primers are used; DNA polymerase initiates both strands

42.

Which choice correctly matches tRNA anticodons pairing with mRNA codons during initiation?

a)

A - U; T - A; G - C; C - G

b)

U - A; A - U; C - G; G - C

c)

C - G; A - U; G - C; U - A

d)

G - C; C - G; U - A; A - U

43.

Which is the correct sequential order of stages in transcription initiation and elongation in prokaryotes?

a)

Promoter recognition → Open complex formation → Initiation of RNA synthesis → Promoter clearance → Elongation

b)

Elongation → Promoter recognition → Promoter clearance → Open complex formation

c)

Promoter clearance → Elongation → Open complex formation → Promoter recognition

d)

Termination → Elongation → Initiation → Promoter recognition

44.

Which order correctly represents major steps in protein translation?

a)

(1) Initiator tRNA binds start codon; (2) Small ribosomal subunit binds mRNA at start codon; (3) Large subunit joins; (4) Peptide bond formation and translocation; (5) Termination at stop codon

b)

(1) Small subunit binds mRNA; (2) Initiator tRNA binds start codon; (3) Large subunit joins; (4) Elongation; (5) Termination

c)

(1) Termination; (2) Elongation; (3) Initiation; (4) Peptide bond; (5) Large subunit joins

d)

(1) Elongation; (2) Initiation; (3) Termination; (4) Peptide bond; (5) Small subunit binds

45.

Which best explains the high fidelity of information transfer from DNA to mRNA during transcription?

a)

Self-complementarity of the mRNA strand

b)

Base-pairing specificity guided by enzymes

c)

Unique shape of tRNA

d)

Presence of splicing and nucleotides only

46.

Reverse transcription is the process of synthesizing which molecule using which template?

a)

DNA from RNA

b)

RNA from DNA

c)

Protein from mRNA

d)

mRNA from protein

47.

The figure shows a DNA double helix used as a template to synthesize a complementary RNA strand (labeled RNA) by base pairing along a single DNA strand. What cellular process does the figure depict?

a)

Transcription

b)

Reverse transcription

c)

Replication

d)

Translation

48.

Which statement about genetics is NOT accurate?

a)

The triplet on tRNA is called a codon.

b)

The genetic code consists of nucleotide triplets that specify the amino acid sequence.

c)

Each codon specifies one amino acid.

d)

Triplets that encode information are located on one strand of DNA.

49.

Which statement about the genetic code is correct?

a)

It is identical for all organisms with no exceptions.

b)

All 64 triplets encode amino acids.

c)

An anticodon on tRNA is complementary to an mRNA codon.

d)

Each mRNA molecule has one start codon and three stop codons.

50.

Regarding start and stop codons in translation, which statement is NOT correct?

a)

Prokaryotes and eukaryotes share the same start codon.

b)

The start codon is located near the 5' end of mRNA.

c)

The start codon does not code for an amino acid.

d)

The start codon sequence is AUG.

51.

What is the role of a polysome (polyribosome) during translation?

a)

It produces many different polypeptides at once.

b)

It allows one ribosome to translate many mRNAs simultaneously.

c)

It increases the number of identical polypeptide chains synthesized from one mRNA.

d)

It increases the length of each polypeptide chain.

52.

During DNA replication, short primers are required before DNA polymerase can synthesize new DNA strands. Which statement is NOT correct?

a)

Primers provide a free 3' end to begin synthesis.

b)

Primers are DNA segments.

c)

Primers are RNA segments.

d)

After synthesis, primers are replaced with DNA.

53.

A viral DNA sample is insufficient to identify the pathogen. To create large numbers of DNA copies from the sample, which mechanism-based method should be used?

a)

DNA replication (PCR)

b)

Transcription

c)

Reverse transcription

d)

Translation

54.

Which cellular process is illustrated by the figure showing a replication bubble with two forks, leading and lagging strands synthesized in opposite directions according to 5'→3' synthesis by DNA polymerase?

a)

DNA replication

b)

Gene transcription

c)

Polypeptide translation

d)

Gene regulation

55.

Why, at each replication fork (Y-shaped structure), is only one of the two new DNA strands synthesized continuously while the other is synthesized discontinuously?

a)

Because the two template strands have different base-pairing rules.

b)

Because the two template strands run antiparallel, but DNA polymerase synthesizes only in the 3'→5' direction.

c)

Because the two template strands run antiparallel, but DNA polymerase synthesizes only in the 5'→3' direction.

d)

Because nucleotides on the two templates attach at different times.

56.

In semiconservative DNA replication, which statement correctly describes the outcome?

a)

Replication occurs in the nucleus during interphase.

b)

Each newly formed DNA molecule contains one parental strand and one newly synthesized strand.

c)

Of the two new DNA molecules, one is identical to the parent while the other differs in structure.

d)

The two newly formed DNA molecules are completely identical to each other and to the parent molecule.

57.

In E. coli, at which level does gene regulation primarily occur?

a)

Transcriptional level

b)

Before transcription begins

c)

Translational level

d)

Post-translational level

58.

The main content of gene expression regulation is to:

a)

Control only the transcription of genes.

b)

Control the production of gene products.

c)

Control the DNA replication of genes.

d)

Control the processing of mRNA only.

59.

According to Jacob and Monod, which components make up the lac operon?

a)

lacI gene, structural genes, promoter (P)

b)

Promoter (P), operator (O), structural genes

c)

lacI gene, structural genes, operator (O)

d)

lacI gene, structural genes, operator (O), promoter (P)

60.

What is an operon?

a)

A DNA segment containing several structural genes and one regulatory gene that directly controls them

b)

A cluster of genes on DNA that are co-regulated

c)

A DNA segment containing many structural genes only

d)

A cluster of structural genes controlled together by a single regulatory mechanism

61.

In the lac operon of E. coli, which site is the binding site for RNA polymerase to initiate transcription of the structural genes lacZ, lacY, and lacA?

a)

Operator

b)

Structural genes (lacZ, lacY, lacA)

c)

Promoter

d)

Regulatory gene lacI

62.

Which component is NOT part of the structural organization of the lac operon in E. coli?

a)

Regulatory gene lacI

b)

Promoter region

c)

Structural genes (lacZ, lacY, lacA)

d)

Operator region

63.

How does the lacI gene regulate the lac operon?

a)

It encodes a protein that is part of RNA polymerase.

b)

It encodes a protein that binds the promoter region.

c)

It encodes a repressor protein that binds the operator region.

d)

It encodes a structural protein.

64.

Which of the following is NOT a component of the lac operon proper (i.e., excluding the separately located regulatory gene)?

a)

Operator (O)

b)

lacI gene

c)

Promoter (P)

d)

Structural genes (lacZ, lacY, lacA)

65.

In regulation of the lac operon, what is the role of allolactose?

a)

It binds the repressor and inactivates it.

b)

It binds the promoter to activate transcription.

c)

It binds the structural genes to activate transcription.

d)

It binds the operator to activate transcription.

66.

Which statement correctly evaluates the activity of the lac operon in E. coli when lactose is present?

a)

When lactose is present, the repressor binds RNA polymerase and changes its conformation so it can bind the operator.

b)

When lactose is present, RNA polymerase cannot bind the promoter.

c)

When lactose is present, allolactose inactivates the repressor so it does not bind the operator, allowing transcription.

d)

When lactose is absent, the repressor binds RNA polymerase and prevents it from binding the promoter.

67.

In the regulatory mechanism of the lac operon, which event occurs both when lactose is present and when it is absent?

a)

Some tRNA molecules are synthesized.

b)

The lacI gene is transcribed to produce the repressor protein.

c)

The structural genes Z, Y, and A are transcribed into their respective tRNAs.

d)

RNA polymerase binds the promoter and transcribes the operon.

68.

Which statement about gene regulation is incorrect?

a)

In prokaryotes, gene regulation occurs mainly at the transcriptional level.

b)

Gene regulation mainly adjusts the amount of gene product produced.

c)

When lactose is present, the lacI regulatory gene is not transcribed.

d)

In organisms, gene regulation can occur at multiple levels.

69.

Trong hệ mô hình operon Lac, vì sao protein ức chế bị mất tác dụng?

a)

Vì lactozơ làm mất cấu hình không gian của nó.

b)

Vì protein ức chế bị phân hủy khi có lactozơ.

c)

Vì lactozơ làm gen điều hòa không hoạt động.

d)

Vì gen cấu trúc làm gen điều hòa bị bất hoạt.

70.

Trong cấu trúc của operon Lac, nếu đột biến làm mất một đoạn phân tử ADN thì trường hợp nào sau đây sẽ vẫn tổng hợp được các sản phẩm cấu trúc?

a)

Mất vùng khởi động.

b)

Mất vùng vận hành.

c)

Mất gen điều hòa.

d)

Mất một gen cấu trúc.

71.

Quan sát sơ đồ hoạt động của Operon Lac ở vi khuẩn E. coli trong môi trường nuôi cấy như hình kèm. Phân tích và cho biết phát biểu nào đúng về trạng thái hoạt động của operon.

a)

Vi khuẩn đang được nuôi cấy trong môi trường có đường lactose.

b)

Chất X là enzyme β-galactosidase.

c)

Hai vùng P và O tương tác liên kết với enzyme RNA polymerase.

d)

Operon Lac của vi khuẩn E. coli đang ở trạng thái không hoạt động.

72.

Xét một operon Lac ở E. coli, khi môi trường không có lactozơ nhưng enzym chuyển hóa lactozơ vẫn được tạo ra. Những mô tả nào sau đây có thể giải thích hiện tượng?

a)

Do vùng khởi động (P) bị hoạt hóa nên enzyme ARN polymeraza có thể bám vào để khởi động phiên mã.

b)

Do gen điều hòa (R) bị đột biến nên không tạo được protein ức chế.

c)

Do biến nạp kém hiệu quả, bộ gen (I) bị biến nạp liên kết được với protein ức chế.

d)

Do các gen cấu trúc (Z, Y, A) bị đột biến làm tăng khả năng biểu hiện của gen.

73.

Hệ gene là

a)

Toàn bộ trình tự các nucleotide trên DNA có trong tế bào của cơ thể sinh vật.

b)

Toàn bộ các bào quan trong tế bào của sinh vật.

c)

Toàn bộ RNA trong tế bào của sinh vật.

d)

Toàn bộ plasmid trong tế bào của sinh vật.

74.

Hệ gene của sinh vật nhân thực bao gồm

a)

Tập hợp phân tử DNA trên NST trong nhân tế bào và trong bào quan ti thể, lục lạp.

b)

Tập hợp các phân tử DNA trong vùng nhân và plasmid.

c)

Tập hợp các phân tử DNA trên NST trong nhân và trong bào quan ti thể, lục lạp.

d)

Tập hợp phân tử DNA trên NST trong nhân tế bào và plasmid.

75.

Hệ gene của sinh vật nhân sơ bao gồm

a)

Tập hợp phân tử DNA trên NST trong nhân tế bào và trong bào quan ti thể, lục lạp.

b)

Tập hợp các phân tử DNA trong vùng nhân và DNA plasmid.

c)

Tập hợp phân tử DNA trên NST trong nhân tế bào và trong bào quan ti thể, lục lạp.

d)

Tập hợp phân tử DNA trên NST trong nhân tế bào và plasmid.

76.

Đột biến điểm gồm các dạng

a)

Mất, thêm một cặp nucleotide.

b)

Mất, thêm hoặc thay thế một cặp nucleotide.

c)

Mất, thêm, thay thế hoặc đảo một cặp nucleotide.

d)

Mất, thêm hoặc thay thế một vài cặp nucleotide.

77.

Thể đột biến là

a)

Những cơ thể mang gen đột biến đã biểu hiện thành kiểu hình.

b)

Những cơ thể mang đột biến gen hoặc đột biến NST.

c)

Những cơ thể mang đột biến gen trội hoặc đột biến gen lặn.

d)

Những cơ thể mang đột biến nhưng chưa được biểu hiện ra kiểu hình.

78.

Mức độ gây hại của alen đột biến đối với thể đột biến phụ thuộc vào

a)

Tác động của các tác nhân gây đột biến.

b)

Điều kiện môi trường sống của thể đột biến.

c)

Tổ hợp gen mang đột biến.

d)

Điều kiện môi trường và tổ hợp gen mang đột biến.

79.

Trong số các dạng đột biến sau đây, dạng nào thường gây hại nghiêm trọng nhất?

a)

Mất một cặp nucleotide.

b)

Thêm một cặp nucleotide.

c)

Thay thế một cặp nucleotide.

d)

Đột biến mất đoạn NST.

80.

Hoá chất 5-BU gây đột thay thế cặp nucleotide nào sau đây?

a)

A–T → G–C.

b)

T–A → G–C.

c)

G–C → A–T.

d)

G–C → T–A.

81.

Dạng đột biến nào sau đây không làm thay đổi số lượng thành phần nucleotide của gen?

a)

Thay thế cặp A–T bằng cặp G–C.

b)

Mất một cặp nucleotide.

c)

Thêm một cặp nucleotide.

d)

Thay thế cặp A–T bằng cặp T–A.

82.

Những biến đổi trong cấu trúc của gen, liên quan đến một hay một số cặp nucleotide được gọi là

a)

Alen mới.

b)

Đột biến gen.

c)

Đột biến điểm.

d)

Thể đột biến.

83.

Những biến đổi trong cấu trúc của gen, liên quan đến một cặp nucleotide duy nhất gọi là

a)

Alen mới.

b)

Đột biến gen.

c)

Đột biến điểm.

d)

Thể đột biến.

84.

Những cơ thể mang gen đột biến đã biểu hiện thành kiểu hình được gọi là

a)

Alen mới.

b)

Đột biến gen.

c)

Thể đột biến.

d)

Đột biến điểm.

85.

Hình mô tả dưới đây thuộc dạng đột biến nào?

a)

Thêm một cặp nucleotide.

b)

Mất một cặp nucleotide.

c)

Thay thế hoặc đảo một cặp nucleotide.

d)

Mất, thêm hoặc thay thế một vài cặp nucleotide.

86.

To test his hypothesis, which type of cross did Mendel use?

a)

Reciprocal cross

b)

Test cross

c)

Self-pollination

d)

Outcrossing

87.

How did Mendel obtain pure-breeding white-flowered and purple-flowered pea plants?

a)

Reciprocal crossing

b)

Self-pollination over many generations

c)

Test cross

d)

Crossing unrelated lines

88.

What organism did Mendel use for his genetic studies?

a)

Garden pea

b)

Fruit fly

c)

Four o’clock plant

d)

E. coli

89.

In peas, which cross should be performed to determine whether a dominant phenotype is heterozygous or homozygous?

a)

AA × AA

b)

AA × aa

c)

Aa × Aa

d)

AA × Aa

90.

According to Mendel’s first law, what separates during gamete formation?

a)

Homologous chromosomes always stay together

b)

Alleles of a gene segregate

c)

Different genes always assort together

d)

Traits blend

91.

Which Mendelian principle explains that allele pairs of different genes separate independently during gamete formation when they are on different chromosomes?

a)

Segregation

b)

Independent assortment

c)

Linkage

d)

Blending inheritance

92.

In a monohybrid cross Aa × Aa, what proportion of the F2 phenotype is recessive?

a)

25%

b)

50%

c)

75%

d)

12.5%

93.

In a monohybrid test cross Aa × aa, what fraction of the offspring are expected to show the dominant phenotype?

a)

0%

b)

25%

c)

50%

d)

75%

94.

If two heterozygotes AaBb are crossed and the genes assort independently, what fraction of the offspring are expected to be aabb?

a)

1/16

b)

1/8

c)

1/4

d)

3/16

95.

A dihybrid cross AaBb × AaBb with independent assortment produces what phenotypic ratio in the F2 generation?

a)

9:3:3:1

b)

3:1

c)

1:2:1

d)

1:1

96.

Which statement best defines a gene?

a)

A visible trait

b)

A DNA segment that encodes a product

c)

A dominant character

d)

A chromosome

97.

Which statement best defines an allele?

a)

Alternative versions of a gene

b)

A type of chromosome

c)

A phenotype

d)

A locus with only one form

98.

In meiosis, when do alleles of a gene segregate?

a)

During mitotic anaphase

b)

During meiosis I when homologs separate

c)

During meiosis II when sister chromatids separate

d)

During fertilization

99.

Which principle did Mendel infer from the observation that traits can reappear in the F2 after disappearing in the F1?

a)

Dominance

b)

Segregation

c)

Linkage

d)

Uniformity

100.

In a cross of Aa × aa, what is the expected genotypic ratio among the offspring?

a)

1 AA : 2 Aa : 1 aa

b)

1 Aa : 1 aa

c)

3 AA : 1 aa

d)

All Aa

101.

In peas, round seed (R) is dominant to wrinkled (r). A plant with round seeds is test-crossed and yields 50% round and 50% wrinkled seeds. What is the genotype of the round-seeded parent?

a)

RR

b)

Rr

c)

rr

d)

Cannot be determined

102.

A dihybrid test cross AaBb × aabb (independent assortment) produces which phenotypic ratio?

a)

1:1:1:1

b)

9:3:3:1

c)

3:1

d)

1:2:1

103.

In the absence of mutation, if multiple allele pairs reside on different homologous chromosome pairs, which is true during meiosis?

a)

All genes form one linkage group

b)

Allele pairs assort independently during meiosis

c)

Different nucleotides pair with each other

d)

All traits are determined by one gene

104.

In humans, skin color arises from several gene pairs with additive effects. Which inheritance pattern is this?

a)

Monogenic inheritance

b)

Polygenic inheritance (quantitative)

c)

Cytoplasmic inheritance

d)

Simple dominance

105.

When two heterozygous parents for a single gene show incomplete dominance, what is the expected F2 phenotypic ratio from selfing the F1?

a)

1:2:1

b)

3:1

c)

9:3:3:1

d)

1:1

106.

In a species where coat color is controlled by one gene with two alleles showing codominance, crossing two heterozygotes yields what phenotypic ratio?

a)

1:2:1

b)

3:1

c)

All one phenotype

d)

9:3:3:1

107.

In a trihybrid cross AaBbCc × AaBbCc with independent assortment, what fraction of offspring will be aabbcc?

a)

1/8

b)

1/16

c)

1/32

d)

1/64

108.

A true-breeding tall plant is crossed with a true-breeding dwarf. The F1 are all tall. When the F1 are selfed, what fraction of F2 are dwarf?

a)

1/2

b)

1/3

c)

1/4

d)

3/4

109.

In humans, curly hair (C) and straight hair (c) show incomplete dominance; heterozygote Cc is wavy. If both parents are wavy, what is the probability their child has straight hair?

a)

1/2

b)

1/4

c)

3/4

d)

1/3

110.

A plant with genotype AaBb is test-crossed with aabb. If independent assortment holds, what proportion of offspring are expected to be AaBb?

a)

1/4

b)

1/2

c)

3/4

d)

1/8

111.

Given one gene with complete dominance where A confers tall and a confers dwarf, cross Aa × aa. What fraction of tall plants is expected?

a)

0

b)

1/4

c)

1/2

d)

3/4

112.

In humans, color blindness is an X-linked recessive trait. A carrier woman (XcX) marries a normal man (XY). What fraction of their sons will be color-blind?

a)

0

b)

1/4

c)

1/2

d)

3/4

113.

Which chromosome system determines sex in humans?

a)

XO/XX

b)

ZW/ZZ

c)

XX/XY

d)

Haplodiploidy

114.

In humans, a son inherits his X chromosome from which parent?

a)

Father

b)

Mother

c)

Either parent

d)

Neither

115.

In humans, a son inherits his Y chromosome from which parent?

a)

Father

b)

Mother

c)

Either parent

d)

Maternal grandfather

116.

If a trait is X-linked recessive, which of the following cross outcomes is most typical when an affected male mates with a homozygous normal female?

a)

All daughters affected

b)

All sons affected

c)

All daughters carriers, all sons normal

d)

Half the sons affected, half the daughters affected

117.

Thomas Hunt Morgan’s experiments with Drosophila revealed which key concept?

a)

Traits are blended during inheritance

b)

Genes are located on chromosomes and can be sex-linked

c)

Only autosomes carry genes

d)

Mitochondria determine eye color

118.

In Drosophila, white eye is X-linked recessive to red eye. A white-eyed male is crossed with a homozygous red-eyed female. What is the F1 phenotype distribution?

a)

All offspring white-eyed

b)

All daughters red-eyed, all sons red-eyed

c)

All daughters red-eyed, all sons red-eyed carriers

d)

All daughters red-eyed, all sons red-eyed (no white)

119.

A man with normal vision and a carrier woman for color blindness have a daughter with normal vision. What is the probability this daughter is a carrier?

a)

0

b)

1/4

c)

1/2

d)

1

120.

In birds (ZW system), which sex is heterogametic?

a)

Male

b)

Female

c)

Both

d)

Neither

121.

Which term describes many genes contributing additively to a single trait, producing continuous variation?

a)

Epistasis

b)

Polygenic inheritance

c)

Incomplete dominance

d)

Pleiotropy