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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
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