[Part 3]- B12- reproduction 🧬

Question 1

What does the term ‘genotype’ mean ?

Answer 1

• a genotype, describes the genetic makeup of an individual [what alleles it has].
• for example, a mouse could have the could a bb or BB genotype

Question 2

What is an allele ?

Answer 2

• an allele, is a version of a particular gene

Question 3

What does homozygous mean ?

Answer 3

• homozygous, means the two alleles of a particular gene are exactly the same version of a gene

Question 4

What is a homozygote ?

Answer 4

• a homozygote, is an individual who has two identical alleles [e.g- BB or bb]

Question 5

What is a phenotype ?

Answer 5

• a phenotype, is the observable characteristics of an organism [e.g- black hair or brown fur]

Question 6

What does genotype 🆚 phenotype ?

Answer 6

• a genotype, describes the genetic makeup of an individual [what alleles it has].
• for example, a mouse could have the could a bb or BB genotype
• ; - a phenotype, is the observable characteristics of an organism [e.g- black hair or brown fur]

Question 7

What does heterozygous mean ?

Answer 7

• heterozygous, means the two alleles of a specific gene are different versions of the same gene
• [think hetero- different- a person who is heterosexual, is attracted to a different gender than them; however heterozygous, means different versions of the same gene]

Question 8

What is a heterozygote ?

Answer 8

• a heterozygote, is an individual who has two different alleles for the same characteristic

Question 9

What is a dominant allele ?

Answer 9

• a dominant allele, is an allele that is always expressed in the heterozygote and a dominant allele is always represented by a capital letter
• for example, mice that have the genotype Bb will have the phenotype for black hair only

Question 10

What is a recessive allele ?

Answer 10

• a recessive allele, is an allele that is not expressed in the heterozygote and is always represented by a small letter

Question 11

• Fill in the gaps: although some characteristics are controlled by a ______ gene, most characteristics are the result of many genes ______ together [e.g- height]

Answer 11

• although some characteristics are controlled by a single gene, most characteristics are the result of many genes acting together [e.g- height]

Question 12

What does the term ‘homozygous dominant’ mean ?

Answer 12

• homozygous dominant, means two identical dominant alleles [e.g- BB]

Question 13

What does the term ‘homozygous recessive mean’ ?

Answer 13

• homozygous recessive, means two identical recessive alleles [e.g- bb]

Question 14

What is cystic fibrosis ?

Answer 14

• cystic fibrosis, is a disorder of cell membranes

Question 15

What allele is cystic fibrosis caused by ?

Answer 15

• cystic fibrosis is caused a gene, that has two recessive alleles [e.g- cc]
• this means, a person must have two copies of the defective [recessive] allele, in order to have cystic fibrosis

Question 16

• Fill in the gaps: the allele for normal cell membrane is ________

Answer 16

• the allele for normal cell membrane is dominant [e.g- CC]

Question 17

What is a carrier ?

Answer 17

• a carrier, is an individual who “carries” and can pass on to its offspring a genomic variant [allele] associated with a disease [or trait]

Question 18

What is polydactyl ?

Answer 18

• polydactyl, is an inherited disorder caused by a dominant allele, in which a person may have extra toes or fingers

Question 19

TRUE OR FALSE: a person with polydactyl cannot be a carrier, as if they have one [dominant] allele, they will have polydactyl.

Answer 19

• true- a person with polydactyl cannot be a carrier, as if they have one [dominant] allele, they will have polydactyl.
• this is because, a dominant allele is always expressed, if only one copy is dominant

Question 20

What is embryo screening ?

Answer 20

• embryo screening, is when embryos are tested to see if they have the alleles for inherited disorders

Question 20

What’s a social issue concerning embryo screening ?

Answer 20

• embryos may be able to be screened to produce offspring with desirable features [such as being taller]
• ; this holds social issues because some may see this as unethical- since it could lead to a rise in demand of ‘designer babies’

Question 20

What is an economic issue concerning embryo screening ?

Answer 20

• embryo screening is expensive, so some people think that the money should be spent elsewhere in the health service

Question 21

What’s an ethical issue concerning embryo screening ?

Answer 21

• often a large number of embryos are created; only a small number of embryos are implanted
• this means, some healthy embryos are destroyed, and some people may argue this is unethical because it destroys a potential human life

Question 22

What is gene therapy ?

Answer 22

• gene therapy, is when faulty alleles are corrected to treat inherited disorders [; this is experimental]