YR3-K16-LSN8H

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 3

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CHAPTER 16

INHERITANCE

• I know what selective breeding is and how it is used to benefit humans.
• I know what genetic engineering is and can name and explain various examples.
• I know what transgenesis is and can name and explain various examples.
• I know what CRISPR is and can name and explain various examples.

• SELECTIVE BREEDING
• GENETIC ENGINEERING
• GENE THERAPY
• TRANSGENESIS
• CRISPR

QUIZ LESSON 1-5

INHERITANCE

IDENTICAL TWINS

Figure 1 shows a picture of Dresie and Casie from West-Transvaal, South-Afrika: a white identical twins. Two claims are made about these twins:

Claim 1: “the difference between the ears of Dresie and Casie was already present at birth, therefore this difference is part of the genotype.” 

Claim 2: “these twins have the same blood type.” 

 1.a) Choose which claim is or which claims are true.

b) Explain why your choice(s) by question a is/are true.

IDENTICAL TWINS

 1.a) Choose which claim is or which claims are true. 

STATEMENT 2

b) Explain why your choice(s) by question a is/are true.

Since Dresie and Casie are identical twins their genotype is identical, therefore the difference between the ears cannot be genetic (maybe due to birth) and their blood type has to be identical. Therefor, claim 2 is correct. 

IDENTICAL TWINS

Tongue rolling

People who are capable of rolling their tongue (see figure 2) possess allele R. A person who can’t roll his tongue (rr) has two sisters who can roll their tongue. Both parents are also capable of rolling their tongue. 

2. a) What are the possible genotypes of the sisters?

b) Using your knowledge of punnett squares and “the 6 steps”, try to work out what you think the genotypes of both parents are. Show your work!

IDENTICAL TWINS

2. a) What are the possible genotypes of the sisters?

RR or Rr

b) Using your knowledge of punnett squares and “the 6 steps”, try to work out what you think the genotypes of both parents are. Show your work!

LABRADORS

Snout colour of Labradors

A certain gene determines the snout colour of Labrador dogs. This gene can cause the snout to be black or brown coloured. A male dog homozygous for brown snout colour copulates with five homozygous black female dogs. All puppy’s which are born (F1) from these crossings are interbred. From this interbreeding many puppies are born (F2). Determine the chance for a puppy in F2 to have a brown snout. 

3 Determine the probability for a puppy in F2 to have a brown snout. (Remember to use and show your 6 steps!)

LABRADORS

3 Determine the probability for a puppy in F2 to have a brown snout. (Remember to use and show your 6 steps!)

CANARIES

Canaries being yellow is carries on an allele which is inherited on the X-chromosome and it is recessive (XE). Embryo’s without an allele E (X) die before being born. In these canaries, unlike in humans, males have two X chromosomes (♂=XEX or XEXE) and females have one X and one Y (♀=XEY). A female canary mates with a homozygous canary male. 

4 Determine the chance that the first male canary chick is heterozygous for this characteristic. (Remember to use and show your 6 steps!)

CANARIES

4 Determine the chance that the first male canary chick is heterozygous for this characteristic. (Remember to use and show your 6 steps!)

ALBINOS

In animals, a rare disease called albinism results in the absence of pigment in cells. This leads to a specific phenotype where the organism lacks fur or skin colour. In humans the allele for albinism is recessive and linked to the X-chromosome (Xa). An albino male and a female heterozygous for this allele are getting children. 

 Determine the chance that their first born is an albino girl.

( 6 steps!)

ALBINOS

Determine the chance that their first born is an albino girl.

SEX CHROMOSOMES

Which of the following statements on sex chromosomes is correct? 

(Just choose a letter, no explanation required!)

 A Sex chromosomes are only present in egg and sperm cells.

B All chromosomes in egg and sperm cells are sex chromosomes.

C Sex chromosomes are present in all cells.

SEX CHROMOSOMES

Which of the following statements on sex chromosomes is correct? 

(Just choose a letter, no explanation required!)

 A Sex chromosomes are only present in egg and sperm cells.

B All chromosomes in egg and sperm cells are sex chromosomes.

C Sex chromosomes are present in all cells.

HOMEWORK FOR LESSON 9:

• COMPLETE THE LESSONUP HW9
• WRITE A SHORT SUMMARY OF THE KEYWORDS COVERED TILL NOW