Chapter 1 – Heredity

Prepared by: GOAD’s Team

IMPORTANT VOCABULARY WORDS

Traits homozygote Character heterozygote

Genes Dominant Allele recessive Genotype phenotype

WHAT IS HEREDITY?

HEREDITY - is a passing of traits from parents to offspring.

Parents offspring

CHARACTER

Height

TRAITS

Tall? Short?

CHARACTER TRAITS

Eye color Brown? Black? Blue?

CHARACTER TRAITS

Skin color Brown? White? Dark?

CHARACTER TRAITS

Hair Curly? Straight?

SMART CHECK: Which of the following examples is a character that can pass from parents to offspring?

A. Guitar skill

B. Blue eyes

C. AB blood type

SMART CHECK:

Which of the following examples is a character that can pass from parents to offspring?

A. Guitar skill B. Blue eyes C. AB blood type

Traits

Understanding Genes, DNA and Chromosomes

MIND-MAPPING Nucleus

Chromosomes

DNA De-oxy-ribo-nucleic acid

Genes

Nucleus Chromosomes DNA Genes

Inside a nucleus are……

The Chromosomes

What is a Chromosome? A thread-like structure that contains DNA.

What is the job of chromosome?

- Wrap the DNA - Guard the DNA

How many chromosomes do humans have?

Sperm = 23 chromosomes + Egg cell = 23 chromosomes

22 chromosomes are called autosomes

1 chromosome is called sex chromosomes

Male = X and Y chromosome Female = XX chromosome

46 Chromosomes

Look at the picture!

SMART CHECK: If a person has X and Y chromosomes, what will be the gender?

A. Male or boy

B. Female or girl

SMART CHECK: If a person has X and Y chromosomes, what will be the gender?

A. Male or boy

B. Female or girl

CHECK YOUR UNDERSTANDING:

If no chromosomes, DNA would be very long and cannot fit inside the cell, That’s why the job of the chromosome is to wrap the DNA.

Now let’s talk about DNA

Nucleus Chromosomes DNA Genes

Inside a chromosome is….

The DNA (de-oxy-ribo-nucleic acid)

What is a DNA?

- a long protein molecule that makes up genes.

What is the function (job) of DNA?

- It has life information and instructions.

- It tells every cell what to do.

4 nucleotides of the DNA Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

They are pairs

They are pairs

What are the jobs of 4 nucleotides?

Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

They are the “bank” of DNA

Save all codes and information

Now let’s talk about Genes

Nucleus Chromosomes DNA Genes

Inside the DNA are….

The Genes

WHAT IS A GENE?

GENE

- is a unit of heredity

- is made up of DNA

What is the function (job) of Genes?

- It carries information to every cell.

- It determines your physical appearance (what you look

like).

Chromosomes

DNA

Genes

They tell the

cell what to do to make human

COMPARISON TO A BOOK

The DNA The ink and pen

nucleotides The letters

genes The sentence

chromosomes The chapter

SMART CHECK:

What is the main job of our genes?

A. Carries DNA

B. Carries information

C. Carries blood

SMART CHECK:

What is the main job of our genes?

A. Carries DNA B. Carries information

C. Carries blood

Genes and Alleles

- Alleles come from genes

DNA genes alleles

Genes and Alleles

DNA

Genes

Genes

Genes

Genes

Alleles

Alleles

Alleles

Alleles

Alleles

Alleles

2 Types of Allele:

1. Dominant

2. Recessive

2 Types of Allele:

1. Dominant - Stronger allele. It can be observed easily.

Brown eye has a stronger allele.

2 Types of Allele:

2. Recessive

- weaker allele and cannot be observed easily

Formula

Dominant + Dominant = DD (Dominant dominant)

Dominant + recessive = Dr (Dominant recessive)

recessive + recessive = rr (recessive recessive)

SMART CHECK:

How can you observe recessive trait?

A. With dominant allele

B. With recessive allele

SMART CHECK:

How can you observe recessive trait?

A. With dominant allele

B. With recessive allele

Understanding Genotype and Phenotype

Genotype Phenotype

Information in genes and alleles

A trait that you can see and observe

Code and information to make blue eyes

meaning

example hair color, eye color, height and weight

Job Prepare and tell the code to phenotype

Do the code to be seen

2 Types of Genotype:

1. homozygous

2. heterozygous

Homozygous

- Same alleles

Heterozygous

- Different alleles

Blue has small “a” and Sky blue has big “A”

SMART CHECK:

The form of the gene that is “weaker” and you cannot see?

A. Dominant B. Recessive C. Phenotype

SMART CHECK: The form of the gene that is “weaker” and you

cannot see?

A. Dominant B. Recessive

C. Phenotype

Can be seen

Can be seen

SMART CHECK:

rr would result in a ______________ genotype.

A. Homozygous B. heterozygous

SMART CHECK:

rr would result in a ______________ genotype.

A. Homozygous

B. heterozygous

SMART CHECK:

If the gene can be seen, it is called ______________________

A. genotype

B. phenotype

SMART CHECK: If the gene can be seen, it is called

______________________

A. genotype

B. phenotype

SMART CHECK: In the picture. Who has a dominant trait?

A. Father B. Mother

SMART CHECK: In the picture. Who has a dominant trait?

A. Father B. Mother

How does heredity (passing of traits) work?

Can you explain how it works?

MAP SUMMARY heredity parents

Passing of traits

offspring

Chromosomes cell

DNA

genes alleles

dominant recessive genotype

phenotype

homozygous

heterozygous