Genetics

Standard:

• HS-LS1-1 Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells.

• HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

• HS-LS1-3 Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.

Learning Intentions:

• Today I will determine the concept of Genetics and its proponent.

• Today I will differentiate dominant and recessive, Homozygous and heterozygous allele.

• Today I will give the correct phenotype and genotype of a certain allele.

Genetics is the study of how genes and how traits are passed down from one generation to the next.

Gregor Mendel- was an Austrian scientist, teacher, and Augustinian prelate who lived in the 1800s. He experimented on garden pea hybrids while living at a monastery and is known as the father of modern genetics.

Traits are determined by the genes on the chromosomes. A gene is a segment of DNA that determines a trait.

Chromosome is a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Chromosomes come in homologous pairs, thus genes come in pairs.

 
Homologous pairs – matching genes – one from female parent and
- one from male parent.

Example: Humans have 46 chromosomes or 23 pairs.

                            
One set from dad – 23 in sperm

One set from mom – 23 in egg

Multiple Choice

How many pairs of chromosomes are there in Humans?

• 46 pair

• 23 pairs

• 40 pairs

• 21 pairs

Multiple Choice

Who is considered as the father of Modern Genetics?

• Charles Darwin

• Robert Hooke

• Gregor Mendel

• Alexander Fleming

Multiple Choice

It is made of protein and a single molecule of deoxyribonucleic acid (DNA) and it is found in the nucleus.

• chromosome

• heredity

• gene

• allele

Multiple Choice

It is defined as the science of genes and how traits are passed on from one generation to the next.

• Heredity

• Genes

• Cell

• Genetics

Genes and Allele

Genes is the basic physical and functional unit of heredity. Genes are made up of DNA and each chromosome contains many genes.

Alleles- are variations of these genes, leading to diverse traits such as eye color.

example:
blue eyes or brown eyes

Multiple Choice

Which of the following describe a Genes?

• It act as instructions to make molecules called proteins.

• They are segments of your DNA, which give physical characteristics that makes everyone unique.

• It code for all of the proteins in our bodies, and are responsible for many of our physical traits.

• All of the choices

Multiple Choice

Which of the following is NOT an example of an allele

• Eye Color

• Green Eyes

• Attached Earlobes

• Blond Hair

Multiple Choice

The following are example of Genes EXCEPT __________.

• Blonde Hair

• Earlobes

• Eye Color

• Hair Color

Multiple Choice

It consist of different genes (possibilities) for the same trait.

Example: blue eyes or brown eyes

• Genes

• Chromosome

• Allele

• Heredity

Dominant and Recessive Genes

Dominant gene- prevents the other gene from “showing”

Recessive gene- it that does NOT “show” even though it is present

Symbol – Dominant gene – upper case letter – T

                      Recessive gene – lower case letter – t

Example:
Straight thumb is dominant to hitchhiker thumb  
T = straight thumb   
t = hitchhikers thumb

(Note: Always use the same letter for
the same alleles—

No S = straight, h = hitchhiker’s)
Straight thumb = TT

Straight thumb = Tt

Hitchhikers thumb = tt

Example:
Straight hair is dominant to curly hair  
S = straight hair   
s = curly hair

Straight hair = SS

Straight hair = Ss

curly hair = ss

Example:
Brown eyes are dominant to blue eyes  
B = brown eyes  
b = blue eyes

Brown Eyes = BB

Brown Eyes = Bb

blue eyes = bb

Multiple Choice

Round seeds are dominant to wrinkled seeds.

R- Round Seeds

r- wrinkled seeds.

What are the possible alleles in order to have a round seeds?

• RR only

• rr only

• Rr and rr

• RR and Rr

Multiple Choice

Pointed heads are dominant to round heads.

P- Pointed heads

p- round heads

What are/is the possible allele for round heads?

• pp only

• PP only

• Pp and pp

• PP and Pp

Fill in the Blank

In humans, Brown eye color (B) is dominant over blue eye color (b).

What are the possible alleles will a human have if he has a brown eye color?

Homozygous and Heterozygous

Homozygous-both genes of a pair are the same or purebred

  Example:
TT – homozygous dominant

     tt  – homozygous recessive

Heterozygous-consist of one dominant and one recessive gene or hybrid

  Example:
Tt – heterozygous

Genotype and Phenotype

Genotype is a combination of genes an organism has (actual gene makeup)

    Ex:  TT, Tt, tt

Phenotype is a physical appearance resulting from gene make-up.

  Ex:  hitchhiker’s thumb or straight thumb

Multiple Choice

The alleles for the colors of the hair of the cat are the following:

B- black

b- brown

What is/are its the possible genotype?

• BB

• BB, Bb

• BB, Bb, bb

• bb only

Multiple Choice

Brown eyed sheep "B" is dominant over blue eyed sheep "b".

If the genotype of the sheep is BB and Bb, what is its phenotype?

• Brown eyed sheep

• Blue eyed sheep

• Both Brown and blue eyes

• None of the choices

Multiple Choice

Pea comb chicken "P" is dominant over Single comb chicken "p".

One of its genotype is "pp".

What is its phenotype?

• Pea comb chicken

• Single comb chicken

• Both pea comb and single comb

• None of the choices

Base from the table, the possible genotype of a Round Seeded Plant are "RR" and "Rr".

If we will get the phenotype of these two genotype these are the following:


Phenotypes are:
Homozygous round seeded plant (RR)

Heterozygous round seeded plant (Rr)

Base from the table, the possible genotype of a Purple Pea Plant are "PP" and "Pp".

If we will get the phenotype of these two genotype, these are the following:


Phenotypes are:
Homozygous purple pea plant (PP)

Heterozygous purple pea plant (Pp)

Base from the table, the possible genotype of a Purple Colored Plant is "ww"

If we will get the phenotype of these this genotype


Phenotypes is:
Homozygous colored plant (ww)

Multiple Choice

Base from the table, what is the genotype of a Homozygous Erect Swine Ears?

• Ee

• ee

• EE

• eE

Multiple Choice

From the table give the genotype of a heterozygous Hairy Sheep Fleece.

• hH

• hh

• HH

• Hh

Multiple Choice

Using the table, what is the genotype of a homozygous red chicken feathers

• Bb

• bb

• bB

• BB

Multiple Choice

From the table, give the phenotype of this genotype "ss".

• curly horse hair

• smooth horse hair

• both curly and smooth horse hair

• none of the choices

Multiple Choice

Using the table, what is the phenotype of this genotype "Bb"

• None of the choices

• Black chicken feathers

• Red chicken feathers

• Both black and red chicken feathers

Multiple Choice

Base from the table, the phenotype of this genotype "CC" is ______________.

• Flaxen mane Horse tail

• Both chestnut and flaxen mane

• Chestnut mane Horse tail

• None of the choices

Summary

Genetics is the study of how genes and how traits are passed down from one generation to the next. The Father of Modern Genetics is Gregor Mendel. Traits are determined by the genes on the chromosomes. A gene is a segment of DNA that determines a trait. Chromosome is a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes. Chromosomes come in homologous pairs, thus genes come in pairs known as Homologous pairs matching genes one from female parent and one from male parent.

Summary

Dominant gene prevents the other gene from “showing” while Recessive gene- it that does NOT “show” even though it is present. The symbol for dominant gene is expressed in upper case letter while recessive gene in lower case letter.
Homozygous both genes of a pair are the same or purebred

 Example:
TT – homozygous dominant

  tt  – homozygous recessive

Heterozygous-consist of one dominant and one recessive gene or hybrid

  Example:
Tt – heterozygous

Genotype is a combination of genes an organism has (actual gene makeup)

    Ex:  TT, Tt, tt
Phenotype is a physical appearance resulting from gene make-up. Ex:  hitchhiker’s thumb or straight thumb

End of the Presentation