YR3-K16-LSN2

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

Get your laptop

make Kwizl ET_CH16_LSN2

8 minutes

Check your own test afterwards

CHAPTER 16

INHERITANCE

KEYWORDS LESSON 2:

• HETEROZYGOUS
• HOMOZYGOUS
• DOMINANT
• RECESSIVE
• ALLELES
• GENOTYPE
• PHENOTYPE
• PUNNETT SQUARES

READ KERBOODLE PAGES 246-252

• I know what heterozygous and homozygous genes are and I can explain the difference.
• I know what genotype and phenotype is and I can explain the difference.
• I understand and can explain the difference between dominant & recessive genes.
• I can use a punnet square to show the inheritance of certain genes.

• HETEROZYGOUS
• HOMOZYGOUS
• DOMINANT
• RECESSIVE
• ALLELES
• GENOTYPE
• PHENOTYPE
• PUNNET SQUARES

KERBOODLE P. 246-252

Karyograms:

1. left male right female
2. left female right female
3. left male right male
4. left female right male

Someone has bloodtype AB, this is determined by:

1. the hair
2. phenotype
3. genotype
4. environment

Check the image.

What is true?

This organism is .....

1. homozygote for the left gene heterozygote for the gene in the middle heterozygote for the right gene
2. heterozygote for the left gene heterozygote for the gene in the middle homozygote for the right gene
3. homozygote for the left gene homozygote for the gene in the middle heterozygote for the right gene
4. homozygote for the left gene heterozygote for the gene in the middle homozygote for the right gene

Genes, alleles, loci en homologous chromosomes

A gene holds information for a type of protein. these proteins together result in (genetic) characteristics.

Each gene lays on a specific spot in the genome called a locus ( mv: loci)

Each gene can have different variants called alleles.

Because a diploid organism has two chromosomes of each pair (homologous chromosome), each diploid organism has  2 loci for each gene which can contain similar or different alleles. 

Two alleles per gene/locus

Two similar alleles for a gene?  HOMOZYGOUS

Two different alleles for a gene? HETEROZYGOUS

Practice assignments in class: #1

Someone's gender is also genetic, in this case I mean the sex you are born with and not the gender you identify with.

a. What alleles/chromosome exist in terms of gender? 

b. What are the parents genotypes? and possible gametes?

c. Show the possible crosses in a punnet squares.

d. What possible outcomes are there. 

Steps with Punnet Squares

1. Identify the alleles.
2. Identify genotype parent 1. Show possible gametes.
3. Identify genotype parent 2. Show possible gametes.
4. Fill in your punnet squares.
5. Write down ratios of the possible genotypes.
6. Write down ratios of the possible phenotypes.

Monohybrid crossing- example

The gene for black coat color is inherited in a dominant way. Two heterozygous black dogs mate. What is the change of getting brown dogs?

Monohybrid crossing- example

How to start? 

1. meaning of the alleles

Black =dominant = A

Brown= recessive = a

The gene for black coat color is inherited in a dominant way. Two heterozygous black dogs mate. What is the change of getting brown dogs?

Monohybrid crossing- example

How to start? 

1. meaning of the alleles

Black =dominant = A

Brown= recessive = a

2. Genotype of parents

     dad = heterozygous = Aa

mom  = heterozygous = Aa 

The gene for black coat color is inherited in a dominant way. Two heterozygous black dogs mate. What is the change of getting brown dogs?

Monohybrid crossing- example

How to start? 

1. Meaning of the alleles

2. Genotype of parents

3. What are the possible gametes

4. Punnett square

The gene for black coat color is inherited in a dominant way. Two heterozygous black dogs mate. What is the change of getting brown dogs?

Punnett squares

possible gametes of parents A, a (dad) en A , a (mom) along the sides (gray)

in cells the combination of the both gametes

Monohybrid crossing- example

How to start? 

1. Meaning of the alleles

2. Genotype of parents

3. What are the possible gametes

4. punnett square

5. ratio of genotypes 

6. ratio of fenotypes

The gene for black coat color is inherited in a dominant way. Two heterozygous black dogs mate. What is the change of getting brown dogs?

Punnett squares

ratio genotype = AA : Aa : aa        ratio phenotype bruine vacht : blonde vacht

                                  1   :  2  :  1                                                          3        :        1

example

change that sperm cell contains recessive allele: 1/2

change that egg cell contains recessive allele: 1/2

change that the zygote contains both recessive alleles 1/2 * 1/2 := 1/4

Rules for punnett squares

Use letter with a clear difference in capital and normal: Rr, Tt, Ee, Aa, Bb

Parent generation = P - From latin "Parentes" / English "Parent"

Offspring =  F₁ - F  from latin "Filii " = children 

                                                   1   indicates the generation 

                                                   (F₁ = 1e generation, F₂ = 2e generation, etc)