• What is DNA?• Where in the cell is DNA found?• Where does it come from?• What are Chromosomes

Copy questions leave 5 lines after each one.

Discussion Questions

• What are some important discoveries in genetics?

• What is the structure and function of DNA?

• Where is DNA located?

• Why are some traits passed from parent to offspring?

• What are the responsibilities of genes?

Preclass: Review Time. Answer in complete sentences.

1. What structure connects chromatids together?

2. All living things rely on _____________to give them the energy they need.

3. _________ is the stage of the cell cycle where the nucleus divides.

4. ________ and ________ are products of photosynthesis.

5. ________ and ________ are raw materials for respiration.

6. What is the structure and function of DNA? How do the nucleotides pair up (AGTC)?

7. • Where is DNA located?

Heredity Preclass

• Copy each term on page 75- using your glossary, write out the definition for each word.

Heredity

Two ways organisms Reproduce

Sexual reproduction– Offspring have

characteristics (traits) from both parents

– These organisms have two parents

• Female-egg cell• Male-sperm cell

Asexual Reproduction

– Offspring look exactly like their parent

– These organisms have one parent

• Bacteria- binary fission• Spores• budding

Heredity- passing of traits from parents to offspring

Traits are recorded on Genes in the form of DNA

Making Sense of Genetic information:

Nucleotide Subunits + Sugar +Phosphate

DNA (instructions) Shape- double helix

Genes (heredity information)

Chromosomes (passed from parent to offspring)

Gregor Mendel

• An experiment was done with pea plants in 1800s in Austria.

• The goal was to find out which traits are dominant and which traits are recessive– Dominant traits- always appears, uses a capital letter

as a symbol of the trait– Recessive traits- recede into the background, uses a

lower case letter as a symbol of the trait

What else did he find out?

• There are different forms of the same gene (allele) – Ex. You have a gene for height but you may have

inherited two forms of height tall or short

• Many genes can influence a singe trait– Ex. Your eyes have color and shape

• One gene can influence many traits– Ex. tiger gene for fur color also controls eye color-

Answer in your journal

• Some people have brown eyes, some have blue, some have green. Some people have earlobes that are attached directly to their head, while others have earlobes that hang loose. Where do people get these traits? How are they passed from one generation to the next?

• Collect DataEar Lobe Free

Widow's Peak Present or Absent

Interlocking Fingers Lf over rt Present 

Tongue Roller  

Hitch-hikers's Thumb

Bent Little Finger

Eye Color Not Blue

Index Finger Short

Dimples

Right Handed  

Experiment Continued

• Analyze your data– Use a sheet of graph paper to show your information

– WHAT ARE THE TRENDS YOU SEE

– ONLY TALK ABOUT YOUR DATA!

• Interpret your data- Draw conclusions• Communicate your results

Draw Conclusions: Take a look Back at your Experiment

– Which traits are dominant according to the information you have. Explain how you know this.

– How could you find out whether or not a trait is dominant or recessive in your family?

– What would you have done differently to figure out if a trait is dominant or recessive?

DNA Structure

• The Shape of DNA is called Double Helix• DNA has a sugar phosphate backbone• DNA is made up of nucleotide subunits

– Adenine

– Thymine

– Guanine

– Cytosine

• Information can be organized using a Punnett Square.– Genotype- the inherited combination of alleles

• Homozygous (same) BB

• Heterozygous (different)Bb

– Phenotype- the expressed trait (what you see on the outside)

HOW TO DO A PUNNETT SQUARE

• A Punnett square is a chart which shows/predicts all possible gene combinations in a cross of parents (whose genes are known). Punnett squares are named for an English geneticist, Reginald Punnett.

Sample Problem -

Step 1. • Designate letters which will represent the

genes/traits. Capital letters represent dominant traits, and lowercase letters represent recessive traits. T = tall t = short

Step 2. • Write down the genotypes (genes) of each

parent. These are often given to you or are possible to determine. TT (tall) X tt (short) - both homozygous (same) or purebred Step 3.

• List the genes that each parent can contribute.– Parent 1

– Parent 2

• Step 4. • Draw a Punnett square - 4 small squares in the

shape of a window. Write the possible gene(s) of one parent across the top and the gene(s) of the other parent along the side of the Punnett square.

Step 5. • Fill in each box of the Punnett square by

transferring the letter above and in front of each box into each appropriate box. As a general rule, the capital letter goes first and a lowercase letter follows.

•

• Step 6.

• List the possible genotypes and phenotypes of the offspring for this cross.

Interpret your data…

• What are the possible genotype(s) of a tall plant?

• What are the possible genotype(s) of a short plant?

• What would be the phenotype of TT?

• What would be the phenotype of tt?

• Why is the phenotype of Tt tall and not medium/average?

How do these traits get passed on during sexual reproduction?

• Sperm Cells (male gametes)- contain half of the genetic information for organisms

• Egg Cells (female gametes)- contain half of the genetic information for organisms

• How many chromosomes do we have?• How are these cells produced?

Meiosis

•

Haploid Haploid Cells- half Cells- half the DNAthe DNA

• Types of twins: • Fraternal - two independent eggs are fertilized by

two independent sperm. Genetically, this type of twins is the same as regular siblings that happen to be born at the same time.

• Identical - one egg is fertilized by one sperm then that zygote splits completely in half to become two people with identical genes (they basically started out as one person with one set of genes).

Making Sense of it all:

Nucleotide Subunits + Sugar +Phosphate

DNA (instructions)

Genes (heredity information)

Chromosomes (passed from parent to offspring

DNA Structure

• The Shape of DNA is called Double Helix• DNA has a sugar phosphate backbone• DNA is made up of nucleotide subunits

– Adenine

– Thymine

– Guanine

– Cytosine

DNA

• How does DNA determine what we look like?– DNA provides the code for making RNA

• RNA is the ribonucleic acid that contains instructions for making amino acids.

• Amino Acids go to the ribosomes to make protiens.

– Proteins are made from amino acid

DNA Replication

• When the DNA is copied errors can happen causing mutations– Substitution- putting one nucleotide pair in the place

of another

– Insertion-adding in a nucleotide pair

– Deletion- removing on nucleotide pair

– Write an example for each one

– Remember: A-T, G-C

EXAMPLES

ORIGINAL SUB DELET. INSERTION

Origin of Species

• Adaptations- changes a species undergoes to enhance survival

• Mutations- permanent changes in DNA• Natural Selection- the most “fit” survive

– Reproduction, finding food, shelter, etc.

Evolutionary Relationships

• Carolous Linnaeus- system of classification or taxonomy