Worksheets8th Grade Genetics March 14, 2025
Total questions: 20
Worksheet time: 13mins
What is the basic unit of DNA called?
gene
nucleotide
chromosome
protein
What are the four nitrogenous bases found in DNA?
adenine, uracil, cytosine, guanine
adenine, thymine, cytosine, guanine
adenine, thymine, uracil, guanine
cytosine, thymine, guanine, uracil
Describe the shape of a DNA molecule.
Single strand
Triple helix
Circular loop
Double helix
How many chromosomes do humans typically have?
48
50
46
44
What is the difference between a gene and a chromosome?
A gene is a complete set of chromosomes found in a cell.
A chromosome is a single DNA molecule that does not contain genes.
A gene is a segment of DNA that codes for a protein, while a chromosome is a structure that contains many genes.
A gene is a type of chromosome that contains multiple proteins.
What is the process by which DNA is copied called?
Replication
Translation
Transcription
Mutation
What is a dominant allele?
A dominant allele is an allele that expresses its trait in the presence of another allele.
An allele that only expresses its trait when paired with another dominant allele.
An allele that does not affect the phenotype of an organism.
An allele that is always recessive regardless of other alleles.
What is a recessive allele?
A recessive allele is always expressed in the phenotype.
A recessive allele is dominant over other alleles.
A recessive allele is an allele that only expresses its trait when two copies are present.
A recessive allele requires only one copy to show its trait.
What inheritance pattern is shown when a trait is expressed in the offspring even if only one parent contributes the allele?
Recessive inheritance
Dominant inheritance
Incomplete dominance
Codominant inheritance
What is the term for the physical expression of a gene?
Chromosome
Phenotype
Allele
Genotype
What is a Punnett square used for?
To measure the height of plants in a field.
A Punnett square is used to predict genetic variations in offspring from parental genotypes.
To determine the color of flowers in a garden.
To calculate the age of an organism.
How can environmental factors influence genetic traits?
Genetic traits are solely determined by DNA without any external influence.
Environmental factors have no impact on genetic traits.
Environmental factors can only affect physical appearance, not genetic traits.
Environmental factors can affect genetic traits by influencing natural selection and causing epigenetic changes.
A mutation is harmful to an organism if it
changes the phenotype of an organism
changes the DNA segment
reduces the organism's chance of survival
makes the organism better able to avoid predators
A physical appearance is
genotype
heterozygous
phenotype
codominance
Two identical alleles for a trait is known as
homozygous
heterozygous
mutation
codominance
Which of the following alleles is homozygous (purebred) recessive?
TT
Tt
tt
ts
Y= yellow pod
y= green pod
What is the percentage of yellow pod when you cross a hybrid pod plant with a purebred green pod plant?
25%
50%
75%
100%
How many pairs of chromosomes exist in each of your cells?
10
12
19
23
This scientist studied pea plants and was considered to be the "Father of Genetics".
Reginald Punnett
Gregor Mendel
Charles Darwin
Rosalind Franklin
What is the probability of producing a tall pea plant from a cross between two hybrid tall pea plants?
25%
50%
75%
100%
