Questions

• How many letters are in the genetic library?

• How many letters make a genetic code word?

• How many genetic words (codons) are in the genetic dictionary?

• How many amino acids are there in total?

• What does a terminator sequence do?

• AIM: How is the genetic code stored in a DNA molecule?

• DO NOW: 2- What is the difference between DNA and RNA?

• HOMEWORK: Textbook read page 305. Reading check page 305.

• AIM: how is the nucleus organized?

• DO NOW: What is DNA and how is it different from RNA?

• Homework: textbook read pages 293,296-297. Do the Reading check questions on pages 293 and 297

DO NOW ANSWER

• DNA: deoxyribose nucleic acid– Found in the nucleus– Holds the genetic code

• Instructions to control all cell activities

• RNA: Ribonucleic acid– Carries the message from DNA out of the

nucleus to the necessary cell parts

Tuesday 2/7/12

• AIM: How does the structure of DNA relate to its function?

• DO NOW: how many chromosomes do your cells have?

• How many genes?• How many nuclei?• Homework: read pages 293,296,297,299.

reading check questions on page 293,296,297

DO NOW ANSWERS

• Somatic cells have 46 chromosomes

• Gametes have 23 chromosomes

• Our cells contain thousands of genes

• Each cell has only one nucleus

YouTube - Structure of DNA

DNA Structure - YouTube

Why do our gametes have only half the number of genes as our

body cells?

DNA: deoxyribonucleic acid• It is one of the polymers

or biomolecules discussed in the past

• Polymer: big molecule made of small repeating units

• Monomer: single unit that bonds with other monomers to build a polymer

• DNA is a chain of Nucleotides

Nucleotide

• The building blocks of nucleic acids• Thousands of nucleotides combine to build

a nucleic acid• There are two types of nucleic acids

– DNA– RNA

• There are slight differences in the structure of the nucleotides that build DNA and RNA

Nucleotide

• The GENERAL or BASIC structure of ALL nucleotides is the same– Phosphate group– 5-carbon sugar– Nitrogen containing

base

DNA nucleotide structure

• Double helix• 5 carbon sugar

(pentose) is deoxyribose

• Adenine• Thymine• Cytosine• Guanine

Structure of DNA double helix• Nucleotides combine to

form: a double helix made up of:– Sugar-phosphate

“backbone”– Nitrogen bases bonded in

the middle

• The double helix consists of 2 anti-parallel complementary strands

• Nitrogen bases are held together by weak Hydrogen bonds

Structure of DNA is a double helix

What do genes do?

Units of heredity that are passed down from generation to

generation

Where are genes located?

On the chromosome which is in the nucleus

How is DNA related to genes and chromosomes?

Wednesday 2/8/12

• AIM: How is the structure of DNA related to its function?

• DO NOW: Why is the nucleolus important?Where in your bodies is DNA stored?

• Homework: textbook Reread page 297. Answer the following questions

1-What are the base pair rules?

2-Which two bases form two hydrogen bonds?

3-Which two bases form three hydrogen bonds?

Nucleolus

• Compacted DNA inside of the nucleus

• Synthesizes RNA

Thursday 2/9/12

• AIM:How do the nitrogen base pairs hold the code for our physical traits?

• DO NOW: 1- Take out last nights homework• 2- If you have a DNA template with the

sequence TACGGTACTGGC what is the complementary DNA strand?

• 3- Explain what the sugar phosphate backbone is.

• HOMEWORK: Textbook page 299 questions 1,3,4,6

Inside of the nucleus

• DNA: deoxyribose nucleic acid– Carries genes on it– Genes are coding regions that build proteins– Proteins lead to physical characteristics– NOT ALL DNA IS MADE UP OF GENES

• Both coding (genes) and non-coding parts of DNA are wrapped around special proteins and form a structure called chromatin

YouTube - Structure of DNA

Why is DNA a double helix?

Two strands of nucleotides that form a spiral when bonded

together

Structure of DNA is a double helix

Use the picture below and tell me how the nitrogen bases are held together

Hydrogen bonds hold nitrogen bases together

Friday 2/10/12

• AIM: how can we build a DNA molecule?• DO NOW: What does it mean when we

say the double helix is antiparallel?• Which part of the nucleotide is responsible

for the double helix being antiparallel?• HOMEWORK: YOU MUST VISIT THE

WEBSITE SPECIFICALLY THE PAGE THAT HAS DNA VIDEOS. View some of the videos

The two strands of DNA are antiparallel

Monday 2/13/12• AIM: How is RNA similar to DNA?• DO NOW: Draw a deoxyribose sugar and number

each carbon properly.• Which number carbon is the phosphate group

connected to? The nitrogen base connected to?• Homework: Textbook read pages 304 to the top of

305 stop reading at RNA: A major player. Answer the following questions:

1- What is gene expression?

2- How do your cells express genes?

3- List and describe the first and second stages of gene expression

Structure of DNA double helix• Nucleotides combine to

form: a double helix made up of:– Sugar-phosphate

“backbone”– Nitrogen bases bonded in

the middle

• The double helix consists of 2 anti-parallel complementary strands

• Nitrogen bases are held together by weak Hydrogen bonds

• What is DNA built from?

• What are the 3 parts of a nucleotide?

• Where is the genetic code in a DNA molecule? In the sequence of codons: 3 nitrogen bases in a row

BASE PAIR RULES

• Always Adenine bonds to Thymine with 2 H bonds

• Cytosine to Guanine with 3 H bonds

• Why is the DNA double helix like a two way street?

• Because the two strands of the double helix run in opposite directions

• 5’-3’

• 3’-5’

• This is determined by the arrangement of the deoxyribose carbons

• Build a DNA Molecule

What is the function of DNA?

Function of DNA is to carry the genetic message from cell to cell

Genetic code

• Gene: specific sequence of DNA that holds the code to build a protein

Tuesday 2/14/12

• AIM: how are RNA and DNA nucleotides different?

• DO NOW: What is the 5 carbon sugar in DNA? In RNA?

• Where is DNA located?• What is the function of RNA?• Homework: textbook page 305. List and

describe the 3 types of RNA. And do the Reading check question on page 305

Gene: unique sequence of base pairs that code for a protein

• DNA is compacted into the nucleus of

the cell

DNA cannot get out of the nucleus

It carries hereditary information (genes)

RNA can leave the nucleus

How can DNA get its information out of the nucleus?

By making an RNA molecule

NucleotidePhosphoric acid=Phosphate group= PO4

-

Structure of a nucleotide is how it is built

PO4- + pentose + nitrogen base

Function of a nucleotide is its job1- To build nucleic acids2- Makes up and carries the genetic code

a. DNA carries the code from cell to cellb. RNA carries the code from inside the

nucleus to the ribosome

Tuesday 2/14/12

• AIM: how are RNA and DNA nucleotides different?

• DO NOW: What is the 5 carbon sugar in DNA? In RNA?

• Where is DNA located?• What is the function of RNA?• Homework: textbook page 305. List and

describe the 3 types of RNA. And do the Reading check question on page 305

Structure of a Nucleotide in RNA and DNA - YouTube

Nitrogen BasesNitrogen Bases

In total there are 5 In total there are 5 nitrogen basesnitrogen bases– Adenine (A)Adenine (A)– Thymine (T)Thymine (T)– Guanine (G)Guanine (G)– Cytosine (C)Cytosine (C)– Uracil (U)Uracil (U)

Thymine builds ONLY Thymine builds ONLY DNA nucleotidesDNA nucleotides

Uracil builds ONLY Uracil builds ONLY RNA nucleotidesRNA nucleotides

DNA vs RNA nucleotide PentoseDNA vs RNA nucleotide Pentose

DNA: 5- carbon sugar DNA: 5- carbon sugar is deoxyriboseis deoxyribose

RNA: 5-carbon sugar RNA: 5-carbon sugar is riboseis ribose

Deoxyribose has one less oxygen than ribose

DNA nucleotide structure

• Double helix• 5 carbon sugar

(pentose) is deoxyribose

• Adenine• Thymine• Cytosine• Guanine

RNA Ribose Nucleic Acid

• 5- carbon sugar is Ribose

• Nitrogen bases• Adenine• Uracil• Cytosine• Guanine

Base pair rules

• DNA• A=T• T=A• C=G

Tuesday 2/16/12

• AIM: Where is the genetic code located?

• DO NOW: Compare DNA and RNA. Make a table showing similarities and differences

• HOMEWORK: textbook pages 313-315. questions 1,2,3,5,6,7,8,11,12,15.

• YOU MAY SEE SOME OF THESE QUESTIONS ON TOMORROW’S EXAM!

Where is RNA synthesized?

nucleolus

DNA(gene): TACTGCATAGTA

1- What is the complementary DNA strand?

2- How many codons are in this gene?

3- What is the primary transcript (RNA) made from this gene?

• END EXAM 2/16/12

• List 5 physical characteristics you have in common with your parents and or siblings.

• How did you get those similar characteristics?

• Physical characteristics are inherited from our parents

• HOW?• Genes: carry the instructions for all

physical characteristics from cell to cell• Where are genes located?• HOW does the genetic code get out of the

nucleus to build the physical characteristic?

• AIM: how are genes organized and carried on the DNA double helix?

• DO NOW: 1- take out last nights homework.• 2- Why do our cells need to get the genetic code

out of the nucleus?• 3- How do our cells get the genetic code out of

the nucleus?• Homework: Textbook Read page307. The

genetic code: three-Letter “words:• 1-Question 1- What is a codon?• 2-Page 310 Questions 1, 2 and 4

• AIM: How are genes organized and carried on the DNA double helix?

• DO NOW: Explain how the structure of DNA is different from the function of DNA.

• HOMEWORK: Textbook Read page 306 to the top of page 307. question 5 on page 310

• Aim: How is RNA synthesized from a DNA template?

• DO NOW: complete the table Structure of Nucleic Acids

Homework: Using the DNA gene sequence

TACGTACCAGCTACT

Create the complementary DNA strand and the primary transcript (mRNA)

DNA: carries genes on it

• Codon: part of a gene sequence

• specific sequence of 3 nucleotides that hold the code for an amino acid

• The nitrogen bases of a codon act as genetic “words”

• When the words are translated,we get an amino acid.

• EX: DNA (gene) TAC

• AIM:How Does transcription create an mRNA molecule?

• DO NOW: 1- Take out last night’s homework

• Where does transcription take place? Why does RNA go to the ribosome? Where is the ribosome?

• Homework: Textbook Read pages 308-309. Reading check page 309

Transcription

• Makes a mRNA from a DNA template

• The purpose is to get the genetic code out of the nucleus into the cytoplasm

• WHY?

• So that a protein can be build which then leads to a physical trait

Gene: unique sequence of base pairs that code for a protein

How is the eukaryotic Nucleus organized?

• Chromosome: key feature to cell division!– DNA double helix wrapped tightly around histone

proteins

• Chromosomes are not DNA!!!!!! • DNA does help make up a chromosome• Total DNA in a single human is about 6 feet long• In order to fit into a cells nucleus, it is compacted

and intertwined with various proteins• But most of the time DNa is in the form of

chromatin

Chromatin: DNA + protein

• But most of the time DNA is in the form of chromatin

Beads on a string

• Nucleosomes: The DNA of chromatin is wrapped around a complex of histones

• Changes in folding between chromatin and the mitotic chromosomes is controlled by the packing of the nucleosome complexes.

Chromatin vs chromosomes

• Chromtin is loosely packed DNA– Form of DNA throughout most of the cell cycle

• Chromosomes are tightly bound chromatin– Only formed during cell division

Organization of DNA

• Chromatin: loosely bound DNA- protein complex that make up chromosomes

• Seen in non-dividing cells• Chromosomes: long complex condensed

molecules of DNA wrapped around histones. During mitosis chromosomes consist of two sister chromatids

• Chromatid:one of two duplicated chromosomes connected at the centromere. They separate to form daughter chromosomes at anaphase

Replicated DNA creates chromatids

Sister chromatids and centromere

Human Chromsomes

• Human: 23 pairs for a total of 46• Homologous chromosome: similar in size,

shape and pattern. (not identical chromosomes)• Automsomes: chromosomes that are not sex

chromosomes. In humans there are 22 pairs• Sex chromosomes: carry genes for sex

determination do not have homologous pairs– Female XX– Male XY

Homologous chromosomes

Homologous chromosomes