DNA and GenesDNA and Genes

Chapter 11 pgs. 280-301Chapter 11 pgs. 280-301

Take out 1 sheet of paper and write both lab Take out 1 sheet of paper and write both lab partners names on it. Discuss and answer partners names on it. Discuss and answer the questions from the powerpoint on the the questions from the powerpoint on the paperpaper

Textbook pg. 280Textbook pg. 2801. Pick one of the 3 bullet points under “1. Pick one of the 3 bullet points under “What What You’ll LearnYou’ll Learn” and explain what you think it ” and explain what you think it means.means.

2. Why is DNA important?2. Why is DNA important?

3. Explain how the characteristics of the 3. Explain how the characteristics of the Shetland pony relate to its DNA?Shetland pony relate to its DNA?

History of DNAHistory of DNA

1800’s Mendel determined that offspring 1800’s Mendel determined that offspring inherited traits from parentsinherited traits from parents

1944 Biomolecule that was involved with 1944 Biomolecule that was involved with heredity was heredity was DNADNA (originally proteins were (originally proteins were thought to pass on traits because DNA thought to pass on traits because DNA was too simple)was too simple)

SCIENCE IS TENTATIVE SCIENCE IS TENTATIVE

Rosalind Franklin Rosalind Franklin and and Maurice WilkinsMaurice Wilkins took took diffracted diffracted photographs of DNAphotographs of DNAX-rays were passed X-rays were passed through DNA crystals, through DNA crystals, the X-rays were bent the X-rays were bent by the atoms in the by the atoms in the DNA molecule DNA molecule producing an image producing an image of the shapeof the shape

1953 1953 Watson Watson & & CrickCrick developed a model of developed a model of DNA using the DNA using the diffraction diffraction photographsphotographs

Double HelixDouble Helix = DNA = DNA comes in 2 long comes in 2 long strands that wrap strands that wrap around each other, around each other, “spiral staircase”“spiral staircase”

Textbook pg. 283Textbook pg. 283

Look at figure 11.2 (don’t forget to read the Look at figure 11.2 (don’t forget to read the caption!)caption!)

44. What is another analogy used for . What is another analogy used for the shape of DNA (besides a the shape of DNA (besides a spiral staircase)?spiral staircase)?

Why is DNA so important?Why is DNA so important?

DNA is known as DNA is known as “blueprint of life”“blueprint of life”

DNA contains DNA contains instructions for instructions for making making proteinsproteins within the cellwithin the cell

GenesGenes are on our are on our chromosomeschromosomes, , chromosomes are chromosomes are made of made of DNADNA

Turn to page 281Turn to page 281Read the paragraph with the heading Read the paragraph with the heading What is What is DNA?DNA?

5. List 3 places in your body that 5. List 3 places in your body that contain proteinscontain proteins

6. Enzymes are a type of protein. 6. Enzymes are a type of protein. Why do we need them?Why do we need them?

Why is DNA so important? Why is DNA so important?

Important for all life Important for all life on Earth, makes each on Earth, makes each individual plant or individual plant or animal uniqueanimal unique

Helps us understand Helps us understand diseases better & find diseases better & find potential curespotential cures

Better food cropsBetter food crops

DNA NucleotidesDNA Nucleotides

DNA is a DNA is a nucleic acid nucleic acid made from subunits made from subunits called called nucleotidesnucleotides

NucleotideNucleotide = 3 parts: = 3 parts: five-carbon sugarfive-carbon sugar, , phosphate groupphosphate group, , nitrogenous basenitrogenous base – DeoxyriboseDeoxyribose = the = the

sugar in a DNA sugar in a DNA nucleotidenucleotide

How the Double Helix stays How the Double Helix stays togethertogether

Double HelixDouble Helix has two has two strands that twist strands that twist together together

One strand of DNA is One strand of DNA is like one half of a zipperlike one half of a zipper– The backbone of the

molecule is alternating phosphates and deoxyribose sugar

– The teeth are nitrogenous bases

phosphates

deoxyribose

bases

One strand of DNA One strand of DNA (half of a zipper) is a (half of a zipper) is a polymerpolymer of of nucleotidesnucleotides

One strand of DNA One strand of DNA has millions of has millions of nucleotidesnucleotides

Nitrogenous BasesNitrogenous Bases

DNA has four different basesDNA has four different bases

CytosineCytosine CC

ThymineThymine TT

AdenineAdenine AA

GuanineGuanine GG

2 kinds of 2 kinds of Nitrogenous BasesNitrogenous Bases

PurinesPurines = double ring = double ring bases, bases, A and GA and G

PyrimidinesPyrimidines = single = single ring bases, ring bases, T and CT and C

Complementary BasesComplementary Bases

Nitrogenous bases Nitrogenous bases on the 2 strands of on the 2 strands of DNA pair up with DNA pair up with one anotherone anotherCytosineCytosine pairs with pairs with GuanineGuanine with with 3 3 (triple) Hydrogen (triple) Hydrogen BondsBondsAdenine Adenine pairs with pairs with ThymineThymine with with 2 2 (double) Hydrogen (double) Hydrogen BondsBonds

Textbook pg. 283Textbook pg. 283

Read the Read the Problem-Solving Lab 11.1Problem-Solving Lab 11.1

Answer the 3 “Thinking Critically” Answer the 3 “Thinking Critically” questions. These will be questions questions. These will be questions numbered 7-9 on your paper.numbered 7-9 on your paper.

DNA ModelDNA Model