Genetics Revision – Year 10 Core Science
Then complete the questions from this revision sheet.
1) What is the scientific term used to describe a person’s genetic information?
2) On the DNA molecule you see to your right label it using the following words:
1.
2.
3.
4.
5.
6.
7.
8.
Adenine
Guanine
Thymine
Cytosine
Sugar
Phosphate
Back bone
Base pair
3) Where is the DNA stored in a cell?
DNA is stored in tightly coiled structures called chromosomes.
4) How many chromosomes in a human body cell?
5) How many chromosomes in a gamete?
6) How many chromosomes in a human haploid cell?
7) Name a haploid cell.
Multiple Choice questions
Question 1
Which of the following is the genotype for a heterozygous individual?
1. TT
2. Tt
3. tt
4. Two different
Question 2
A punnet square is used to:
1. Store strawberries
2. Predict the phenotype of F1
3. Predict the genotype of offspring
4. Record genotypes
Question 3
Which of the following is the genotype for a homozygous recessive individual?
1. TT
2. Tt
3. tt
4. Two different
Question 4
Pure breeding means an individual is:
1. All white
2. Heterozygous
3. Homozygous
4. Has already been crossed
Question 5
What are the possible genotypes of offspring produced from a heterozygous cross? (tongue
rolling=T)
1. TT, tt, Tt
2. Tt, Tt, Tt, tt
3. TT, tt
4. TT, Tt, tt
Question 6
From the information, is tongue rolling a:
1. Recessive phenotype
2. Dominant phenotype
3. Heterozygous phenotype
4. A skill
Question 7
A gene is:
1. Is an allele
2. Is a section of DNA that codes for a protein
3. Aa
4. Is a dominant or recessive feature
BIOLOGY KEY WORD REVISION
Genetics The scientific study of heredity how particular qualities or traits are
transmitted from parents to offspring
Gene - A hereditary unit consisting of a sequence of DNA that occupies a specific
location on a chromosome and determines a particular characteristic in an organism.
Genes undergo mutation when their DNA sequence changes.
Inheritance - each organism’s chromosomes carry characteristics & attributes from
biological hereditary pathways from parents.
Heredity transmitted from parent to child by information contained in the genes
Nucleus part of the cell containing DNA and RNA and responsible for growth and
reproduction
chromosomes – the lengths of DNA that shorten and coil
chromatid -one of two identical chromosomal strands into which a chromosome splits
longitudinally preparatory to cell division
centromere – The central region of a chromosome that holds the two cromatids
together
autosome A chromosome that is not one of the sex chromosomes
sex chromosome an X or Y chromosome. The XX pair determines female, and the XY
pair determines male
diploid – the no. of chromosomes in each body cell is it’s diploid no. – 46 in humans
haploid – the haploid no. is half the number of chromosomes in a cell – 23 in humans
karyotype – the process of sorting chromosomes into their matched pairs.
Karyotyping is important in the study of chromosomal disorders
gamete - a mature sexual reproductive cell having a single set of unpaired
chromosomes
zygote - The cell formed by the union of two gametes
deoxyribonucleic acid A chain of nucleotides (cytosine, guanine, adenine, or thymine)
linked with ribose sugar molecules that form the basis of genetic material. Specific
patterns of nucleotides represent particular genes. It is also the substance of heretiry
traits.
double helix The twisted-ladder shape that two linear strands of DNA assume when
complementary nucleotides on opposing strands bond together
bases (A, T, C, G) The molecular building blocks of DNA and RNA: adenine, cytosine,
guanine, thymine, and (in RNA only) uracil. In DNA, A attaches only to T, and C attaches
only to G. In RNA, A attaches only to U, and C attaches only to G.
sugar phosphate backbone – the backbone of a DNA molecule that contains the A, T, C
and G coding.
Heterozygous-having 2 different alleles for a characteristic
Homozygous- Having identical alleles for a single trait.