10. (a) Explain the following terms that are used in genetics:
(i) Allele
(ii) Heterozygous
(iii) Phenotype - Leaving Cert Biology - Question 10 - 2011
Question 10
10.
(a) Explain the following terms that are used in genetics:
(i) Allele
(ii) Heterozygous
(iii) Phenotype.
(b) In humans, brown eye (B) is dominant to blue eye (... show full transcript
Worked Solution & Example Answer:10. (a) Explain the following terms that are used in genetics:
(i) Allele
(ii) Heterozygous
(iii) Phenotype - Leaving Cert Biology - Question 10 - 2011
Step 1
Explain the following terms that are used in genetics:
(i) Allele
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
An allele is defined as an alternative form of a gene. Genes can have various alleles which contribute to different traits in an organism.
Step 2
(ii) Heterozygous
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Heterozygous refers to an organism that possesses two different alleles for a specific gene. This means that one allele is inherited from each parent, resulting in a genotype, such as Tt (where 'T' and 't' are different alleles).
Step 3
(iii) Phenotype
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Phenotype describes the observable characteristics or traits of an organism, which are determined by the genotype and the environment. For example, the phenotype of a plant might include traits such as its height, flower color, and leaf shape.
Step 4
(b) (i) What is the genotype of the blue-eyed parent?
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The genotype of the blue-eyed parent is 'bb' since blue eyes are a recessive trait.
Step 5
(ii) What are the possible gametes that each parent can produce?
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The heterozygous parent (Bb) can produce two types of gametes: 'B' and 'b'. The blue-eyed parent (bb) can only produce 'b' gametes.
Step 6
(iii) Using a Punnett square or another method work out the possible genotypes and phenotypes of their children.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using a Punnett square, we can visualize the genetic combinations:
B | b
__________
b | Bb | bb
b | Bb | bb
From this, the possible genotypes of the children are 50% Bb (brown eyes) and 50% bb (blue eyes). Therefore, the phenotypes are 50% brown-eyed and 50% blue-eyed.
Step 7
(c) (i) Explain, in terms of what happens to body cells, what is meant by the term cancer.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Cancer occurs when there is an uncontrolled division of body cells, leading to the formation of tumors. This process is characterized by genetic mutations that disrupt normal cell signaling, resulting in cells that continue to grow and divide in an abnormal manner.
Step 8
(ii) Give two possible causes of cancer.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Two possible causes of cancer are:
Exposure to radiation.
Smoking or use of tobacco products.
Step 9
(iii) Some people choose to be screened to determine their risk of getting a particular type of cancer.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Genetic screening is a process that checks for the presence of specific genes that may indicate a heightened risk for developing certain cancers.
Step 10
(iv) What is meant by genetic screening?
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Genetic screening involves testing individuals for specific genetic markers that may suggest a higher risk of developing particular genetic disorders or diseases, such as certain types of cancer.
Step 11
(v) 1. What was used to cut the DNA?
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Restriction enzymes were used to cut the DNA into fragments.
Step 12
2. On what basis were the DNA fragments separated?
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
DNA fragments are typically separated based on their size through a process called gel electrophoresis.
Step 13
3. Give an application of DNA profiling other than solving crime.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
An application of DNA profiling other than solving crimes includes paternity testing, which determines biological relationships between individuals.
Step 14
(v) Using these results, identify which suspect, A, B or C committed the crime.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Based on the DNA profiling results obtained from the crime scene, we identify suspect B as the individual who committed the crime.
Join the Leaving Cert students using SimpleStudy...
