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UNIT 1 INFORMATION METHODS OF A CELL
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UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

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Page 1: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

UNIT 1 INFORMATION METHODS OF A CELL

Page 2: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

What do you know about DNA?• Building blocks are called?

– nucleotides

• The shape is ?– Double helix

• The three primary components of a nucleotide are?– Sugar, phosphate, nitrogen base

• Where are each of these found?– The sugar and phosphate are in the backbone; the nitrogen base is on the rungs between DNA strands

• The sugar is?– deoxyribose

Page 3: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA RNA

Page 4: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA Backbone Structure• Alternate phosphate and sugar (deoxyribose), phosphate ester bonds

Page 5: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA Backbone Structure• Alternate phosphate and sugar (deoxyribose), phosphate ester bonds

Page 6: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA RNA

Page 7: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA RNA

Page 8: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA Primary Structure Summary• Backbone (sugar+phophate with phosphate ester bonds and base side chains)

Page 9: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA RNA

Page 10: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

What are the base pairing rules for DNA?

Page 11: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA Double Helix• Base pairing by unique hydrogen bonds

• C - G and A - T pairs

Page 12: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA Double Helix• Base pairing by unique hydrogen bonds

• C - G and A - T pairs

Page 13: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

• Each strand of the double helix is oriented in the opposite direction

• What is this arrangement called?

• “Antiparallel “

Figure 10.5B

5 end 3 end

3 end 5 end

P

P

P

PP

P

P

P

Page 14: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

What process is used in the cell to make

new strands of DNA?

DNA Replication

Page 15: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA

Page 16: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

What do you remember?

• What does semi conservative replication mean?

– The resulting DNA includes one original strand and one new strand

– One original strand is “conserved” or saved.

Page 17: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Untwisting and replication of DNA

• each strand is a template for a new strand

Figure 10.4B

helicase

DNA polymerase

Page 18: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

What is the job of the helicase enzyme?– To unzip the DNA

What is the job of the DNA polymerases?

– To build new DNA strands by attaching nucleotides to the parent strand

What is the job of ligase?– To attach fragments of DNA together

Page 19: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA Replication• Complementary base pairs form new strands.

Page 20: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

• DNA polymerase works in only one direction

5 end

P

P

Parental DNA

Figure 10.5C

DNA polymerasemolecule

53

35

35

Daughter strandsynthesizedcontinuously

Daughter strandsynthesizedin pieces

DNA ligase

Overall direction of replication

53

• Telomere sequences are lost with each replication.

• Cancer, aging

telomeres

Page 21: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

So what is a telomere anyway?

• A telomere is a repeating DNA sequence (for example, TTAGGG) at the end of the body's chromosomes.

• The telomere can reach a length of 15,000 base pairs. • Telomeres function by preventing chromosomes from losing base pair sequences at their ends. They also stop chromosomes from fusing to each other.

• Each time a cell divides, some of the telomere is lost (usually 25-200 base pairs per division).

• When the telomere becomes too short, the chromosome reaches a "critical length" and can no longer replicate.

• This means that a cell becomes "old" and dies by a process called apoptosis.

Page 22: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

So what do telomeres have to do with

Cancer?• Its all about the enzyme, telomerase.• Telomerase causes the continued addition of DNA ends (telomeres) so cells with active production of telomerase continue to grow and divide. Body cells no longer produce telemerase.

• What kind of cells keep growing and dividing?

• Fetal cells, tumor cells including cancer cells

Page 23: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

• DNA replication begins at many specific sites

How can entire chromosomes be replicated during S phase of the cell cycle?

Figure 10.5A

Parental strandOrigin of replication

Bubble

Two daughter DNA molecules

Daughter strand

What are these sites called?Replication Bubbles

Page 24: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA

Page 25: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA

Page 26: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

• In transcription, DNA helix unzips

– RNA nucleotides line up along one strand of DNA, following the base-pairing rules

– single-stranded messenger RNA peels away and DNA strands rejoin

– What are the 3 steps of transcription?

RNA polymerase

DNA of gene

PromoterDNA Terminator

DNAInitiation

Elongation

Termination

Area shownin Figure 10.9A

GrowingRNA

RNApolymerase

Completed RNA

Figure 10.9B

Page 27: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA

Page 28: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

RNA Transcription• In nucleus, DNA guides the synthesis of mRNA

Page 29: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.
Page 30: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

RNA Transcription• RNA polymerase and elongation reaction

Page 31: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

RNA Transcription• RNA polymerase and elongation reaction

Page 32: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Eukaryotic RNA is processed before leaving the nucleus

• Noncoding segments, introns, are spliced out

• A cap and a tail are added to the ends

Figure 10.10

DNA

RNAtranscriptwith capand tail

mRNA

Exon Intron IntronExon Exon

TranscriptionAddition of cap and tail

Introns removed

Exons spliced together

Coding sequence

NUCLEUS

CYTOPLASM

Tail

Cap

Page 33: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

RNA vs. DNA

• RNA contains Uracil, not Thymine

• Sugar is Ribose• Usually single stranded

Nitrogenous base(A, G, C, or U)

Sugar(ribose)

Phosphategroup

Page 34: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Types of RNA• mRNA contains codons which code for amino acids.

Page 35: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

DNA

Page 36: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Types of RNA• rRNA - Ribosome - contains enzymes and keeps everything together

Page 37: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Types of RNA• tRNA - Transfer RNA carries amino acid and read codons on m-RNA through its

own anticodons.

Page 38: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Types of RNA• tRNA - Transfer RNA carries amino acid and read codons on m-RNA through its

own anticodons.

Page 39: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Protein Synthesis

Page 40: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Protein Synthesis

Page 41: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Protein Synthesis

Page 42: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Protein Synthesis

Page 43: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Protein Synthesis

Page 44: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Check

• The following section of DNA is used to build a strand of mRNA

• 3’ – GAA- CCC- TTT- 5’• What is the corresponding mRNA sequesnce?

• What are the anticodons on the tRNA in the next step?Modified from www.elmhurst.edu/~chm/onlcourse/CHM103/Rx22DNA.ppt

Page 45: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

• Summary of transcription and translation

Figure 10.15

1Stage mRNA istranscribed from aDNA template.

Anticodon

DNA

mRNARNApolymerase

TRANSLATION

Enzyme

Amino acid

tRNA

InitiatortRNA

Largeribosomalsubunit

Smallribosomalsubunit

mRNA

Start Codon

2Stage Each amino acid attaches to its proper tRNA with the help of a specific enzyme and ATP.

3Stage Initiation of polypeptide synthesis

The mRNA, the first tRNA, and the ribosomal subunits come together.

TRANSCRIPTION

Page 46: UNIT 1 INFORMATION METHODS OF A CELL. What do you know about DNA? Building blocks are called? –nucleotides The shape is ? –Double helix The three primary.

Figure 10.15 (continued)

4Stage ElongationGrowingpolypeptide

Codons

5Stage Termination

mRNA

Newpeptidebondforming

Stop Codon

The ribosome recognizes a stop codon. The poly-peptide is terminated and released.

A succession of tRNAs add their amino acids to the polypeptide chain as the mRNA is moved through the ribosome, one codon at a time.

Polypeptide