Genetika Practice Questions
UN (Indonesia) · UN Biologi · 138 free MCQs with instant results and detailed explanations.
138
Total
32
Easy
75
Medium
31
Hard
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Sample Questions from Genetika
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the function of DNA in living organisms?
A.
To provide energy for cellular processes
B.
To store and transmit genetic information
C.
To catalyze biochemical reactions
D.
To facilitate cell division
Show Answer & Explanation
Correct Answer: B
DNA stores and transmits genetic information necessary for the growth, development, and functioning of living organisms.
Q2
Easy
If a pea plant has a genotype of Tt for tallness (T) and shortness (t), which of the following represents the phenotype of this plant?
A.
Short
B.
Tall
C.
Medium
D.
Dwarf
Show Answer & Explanation
Correct Answer: B
The genotype Tt expresses the dominant trait for tallness (T), making the phenotype of this plant tall.
Q3
Easy
In a dihybrid cross of two heterozygous parents (RrYy), what is the probability of obtaining an offspring with the genotype RRYy?
A.
1/8
B.
1/4
C.
1/2
D.
1/16
Show Answer & Explanation
Correct Answer: A
The probability of obtaining the genotype RRYy is 1/8, as it involves two independent events from a dihybrid cross.
Q4
Medium
What is the probability of obtaining a homozygous recessive phenotype from a cross between two heterozygous parents (Aa × Aa)?
A.
25%
B.
50%
C.
75%
D.
0%
Show Answer & Explanation
Correct Answer: A
In a monohybrid cross Aa × Aa, the genotypic ratio is 1 AA : 2 Aa : 1 aa. Therefore, the probability of obtaining the homozygous recessive phenotype (aa) is 1 out of 4, which is 25%.
Q5
Medium
In a population of rabbits, black fur (B) is dominant over white fur (b). If a black rabbit with a genotype of Bb is crossed with a white rabbit (bb), what percentage of the offspring will have black fur?
A.
50%
B.
25%
C.
0%
D.
100%
Show Answer & Explanation
Correct Answer: A
Crossing Bb (black) with bb (white) gives rise to the genotypes Bb and bb in a 1:1 ratio. Therefore, 50% of the offspring will have black fur (Bb) and 50% white fur (bb).
Q6
Medium
Which of the following statements best describes the role of DNA polymerase in DNA replication?
A.
It unwinds the double helix of DNA.
B.
It synthesizes new DNA strands complementary to the template strands.
C.
It repairs damaged DNA.
D.
It binds to RNA primers only.
Show Answer & Explanation
Correct Answer: B
DNA polymerase is responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strands during DNA replication.
Q7
Medium
If a mutation occurs in a gene that codes for a protein involved in the metabolic pathway of a cell, what could be a potential consequence?
A.
Increased efficiency of the pathway
B.
No effect on the organism
C.
Disruption of the metabolic pathway
D.
Enhanced protein synthesis
Show Answer & Explanation
Correct Answer: C
A mutation in a gene that codes for a protein involved in metabolism can disrupt the normal function of the metabolic pathway, leading to potential physiological issues or diseases.
Q8
Hard
In a dihybrid cross between two heterozygous pea plants (YyRr), what would be the expected phenotypic ratio of the offspring for the traits yellow/green seeds and round/wrinkled seeds?
A.
9:3:3:1
B.
3:1
C.
1:1:1:1
D.
1:2:1
Show Answer & Explanation
Correct Answer: A
The expected phenotypic ratio for a dihybrid cross (YyRr x YyRr) is 9:3:3:1, representing the combinations of dominant and recessive traits for two different genes.
Q9
Hard
In a population of fruit flies, the allele for red eyes (R) is dominant over the allele for white eyes (r). If a red-eyed fly is crossed with a homozygous white-eyed fly, what percentage of the offspring will have red eyes?
A.
50%
B.
100%
C.
25%
D.
75%
Show Answer & Explanation
Correct Answer: B
When a homozygous white-eyed fly (rr) is crossed with a red-eyed fly (RR or Rr), if the red-eyed fly is homozygous (RR), all offspring will have red eyes (100%). Even if Rr, 50% will still be red-eyed, but given 'homozygous' condition, it will be 100%.
Q10
Hard
In a dihybrid cross between two pea plants (TtYy x TtYy), where T is tall, t is short, Y is yellow seeds, and y is green seeds, what is the probability of obtaining a homozygous recessive plant?
A.
1/16
B.
3/16
C.
1/4
D.
9/16
Show Answer & Explanation
Correct Answer: A
In a dihybrid cross TtYy x TtYy, the homozygous recessive genotype is ttyy. The probability of tt is 1/4 (1/2 for each Tt) and yy is also 1/4. Therefore, the combined probability is 1/4 * 1/4 = 1/16.
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Genetika — UN (Indonesia) UN Biologi Practice Questions Online
This page contains 138 practice MCQs for the chapter Genetika in UN (Indonesia) UN Biologi. The questions are organized by difficulty — 32 easy, 75 medium, 31 hard — so you can choose the right level for your preparation.
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