Unit 5 DNA, REPLICATION, PROTEIN SYNTHESIS, CELL DIVISION

Unit 5DNA, REPLICATION,

PROTEIN SYNTHESIS, CELL DIVISION

HE.5.B.1: MODEL THE COMPONENTS OF A DNA NUCLEOTIDE AND AN RNA

NUCLEOTIDE.

RNA Nucleotide DNA Nucleotide


NUCLEOTIDE.

RNA Nucleotide DNA Nucleotide


NUCLEOTIDE.

• Sugar is ribose• Bases

include:• Adenine• Guanine• Cytosine• Uracil

• Sugar is deoxyribose• Bases include:• Adenine• Guanine• Cytosine• Thymine

HE.5.B.2: DESCRIBE THE WATSON-CRICK DOUBLE HELIX MODEL OF DNA, USING

BASE-PAIRING RULE.

Note packet page 9


BASE-PAIRING RULE.

•Overall Shape:•Double Helix• (looks like a twisted ladder)


BASE-PAIRING RULE.

•Nitrogen containing bases:• Adenine (A)• Thymine (T)• Cytosine (C)•Guanine (G)


BASE-PAIRING RULE.

• Base Pairing Rules:

• Adenine to Thymine• (A – T)

• Cytosine to Guanine• (C to G)


BASE-PAIRING RULE.

• Backbone:• Phosphate• Sugar (deoxyribose)


BASE-PAIRING RULE.

• Chargaff’s Rules:

• Amount of A always equals amount of T

• Amount of C always equals amount of G

HE.5.B.3: COMPARE AND CONTRAST THE STRUCTURE AND FUNCTION OF DNA

AND RNA.

RNA StructureSingle strandedSugar = riboseBases:

AdenineCytosineGuanineUracil

DNA Structure

Double strandedSugar = deoxyribose

Bases:AdenineCytosineGuanineThymine


AND RNA.

Messenger RNA (mRNA)Carries DNA messages from nucleus to ribosome

Ribosomal RNA (rRNA)Makes up part of the ribosome

Transfer RNA (tRNA)Reads mRNA and carries the correct amino acid to the ribosome


AND RNA.

RNA Function

Instructions for making/controlling all things in the cell


AND RNA.

DNA Function

HE.5.B.4: DESCRIBE AND MODEL THE PROCESSES OF REPLICATION,

TRANSCRIPTION, AND TRANSLATION.

DNA Replication:General Description:

Process of making an exact copy of DNA.



Replication Process:1. Original DNA strands separate2. Complementary nucleotides attach

Use base pairing rules

3. Backbone formed to create new strandSugar and phosphates bond together

4. End Result: Two identical DNA molecules

Each has one original strand and one new strand



Replication: Identify the structures1. Original DNA strands2. Complementary nucleotides3. DNA Polymerase (enzyme)4. Newly constructed DNA Strand



DNA Replication occurs during the Synthesis (S) phase of the cell cycle



Terminology for Protein Synthesis:Transcription: Process of copying a DNA message onto an mRNA molecule.

Translation: Process of translating the message on an mRNA into a protein.



Terminology for Protein Synthesis:mRNA: Carries the DNA message to the ribosome.

tRNA: reads the mRNA message and brings amino acids to the ribosome.

rRNA: makes up part of the ribosome.



Terminology for Protein Synthesis:Codon: 3 letter “word” on mRNA that codes for an amino acid

Anticodon: 3 letter “word” on tRNA that matches the codon

Ribosome: structure in the cell where proteins are made



Central Dogma1. DNA2. Transcription3. mRNA4. Translation5. Protein



Example:DNA: TAC CGG TAA CGC

mRNA: AUG GCC AUU GCG

Amino Acid: Met Ala Ile Ala



DNA determines sequence of mRNAmRNA is grouped into “codons” of 3 letters

Each codon corresponds to a specific amino acid

tRNA brings the correct amino acid to the ribosome

Amino acids link together to make a protein





Transcription Drawing



Translation Drawing

MC.2.B.8: DESCRIBE THE MAIN EVENTS OF THE CELL CYCLE, INCLUDING THE DIFFERENCES IN PLANT AND

ANIMAL CELL DIVISION: INTERPHASE, MITOSIS, CYTOKINESIS

1. Interphase2. Gap 1 (G1) Phase Does normal cell things, Cell grows,

makes more organelles

3. Synthesis (S) phase DNA Replication occurs

4. Gap 2 (G2) phase Same as G1



5. Cell Division (M-phase)6. Mitosis7. Cytokinesis8. Prophase9. Metaphase10.Anaphase11.Telophase12.Cytokinesis



Step 1: Interphase Purpose: Prepare the cell Gap 1 (G1): Normal cell things Cell grows and copies organelles

Synthesis (S): DNA Replication occurs

Gap 2 (G2): Same as G1



Step 2: Mitosis Purpose: divide the nucleus Prophase: Chromosomes condense Nuclear envelope disappears Spindle fibers form



Step 2: Mitosis Metaphase: Chromosomes line up along

equator (middle) Anaphase: Chromosomes pulled to

opposite ends of cell by spindle fibers



Step 2: Mitosis Telophase: Chromosomes uncoil Nuclear envelope re-

appears Spindle fibers disappear



Step 3: Cytokinesis Purpose: divide the cell

(cytoplasm) Occurs after telophase

when there are two nuclei in the cell



Step 3: Cytokinesis In plants: Cell plate forms down

middle of cell Cells break apart



Step 3: Cytokinesis In animals: Cell membrane pinches in Cells pinch apart



Why we need cell division: Growth Growing from a single cell to

an adult requires more cells



Why we need cell division: Replace dead/injured cells Cells must be replaced as

they are lost Example: skin cells

constantly shed and must be replaced



Why we need cell division: Replace cells after illness Immune responses destroy

healthy and sick cells



MC.2.B.9: LIST IN ORDER AND DESCRIBE THE STAGES OF MITOSIS: PROPHASE,

METAPHASE, ANAPHASE, TELOPHASE

PMATP=ProphaseM=MetaphaseA=AnaphaseT=Telophase





Parent Cell: Interphase• Diploid• Somatic (body) cell• DNA is copied

Prophase: • Chromosomes

condense• Nuclear envelope

disappears• Spindle fibers form



Metaphase:• Chromosomes line

up along equator (middle)• Chromosomes

attached to spindle fibersAnaphase: • Chromosomes pulled

apart by spindle fibers



Telophase:• Chromosomes uncoil• Nuclear envelopes

re-appear• Spindle fibers

disappear

MC.2.B.10: ANALYZE THE MEIOTIC MAINTENANCE OF A CONSTANT CHROMOSOME

NUMBER FROM ONE GENERATION TO THE NEXT.





1st division of Meiosis:• Almost identical to mitosis• Difference = chromatids on

homologous chromosomes can switch• Called crossing over



2nd division of Meiosis:• This division cuts chromosome # in

half• Still similar to mitosis• Difference: end up with 4 unique

haploid cells



Purpose of Meiosis:• To create gametes or sex cells that are

haploid

Importance of creating haploid cells:• A gamete has to fuse with another

gamete to make a new individual (fertilization)• If each had full set of chromosomes,

the new individual would have twice as many chromosomes



How does each sex cell become unique:

• Chromosomes line up randomly• Crossing over occurs



Fertilization:

• Fusion of gametes to create a new individual



Egg and Sperm each created through meiosis

Egg and Sperm combine during Fertilization

Fertilization creates a new individual

Egg = Haploid Egg(haploid) +

Sperm(haploid)

= New Individual

Cell (diploid)Sperm = Haploid



Somatic Cells Gametes:

• Body Cells•Diploid

• Sex Cells (egg or sperm)•Haploid



1.Autosomes• Regular

chromosomes• 22 pairs in

humans



2. Homologous Chromosomes• A pair of

chromosomes• 1 from mom• 1 from dad• Same genes on

each one; just different versions



3. Sex Chromosomes• 23rd or last pair

in humans• Determine

gender• Females have XX• Males have XY



Diploid Cell: Haploid Cell:

• Has 2 copies of each chromosome

• These are somatic cells

• Has 1 copy of each chromosome

• These are gametes1 from mom’s egg1 from dad’s sperm

Egg for females

Sperm for males



Diploid Haploid



Mitosis vs. MeiosisMitosis Meiosis

1. Makes diploid cells

1. Makes haploid cells

2. Creates identical cells

2. Creates unique cells

3. Makes somatic cells

3. Makes gametes

4. Used to grow & heal

4. Used to create sex cells for reproduction

5. Cell divides once 5. Cell divides twice



Mitosis:

Diploid Parent Cell

Nucleus then cell divides

DNA Replication

Diploid daughter cells



Meiosis Part I:

Diploid Parent Cell

Nucleus then cell divides

DNA Replication

Diploid daughter cells



Meiosis Part II:

Diploid daughter cells from 1st division

Haploid daughter cells

cell divides again



Haploid Diploid

Human 23 46

Earthworm 18 36



Egg/Sperm Zygote

Maize (corn)

10 20

Dog 36 78

Documents

Unit 5 DNA, REPLICATION, PROTEIN SYNTHESIS, CELL DIVISION