RNA and Protein Synthesis - PowerPoint PPT Presentation

Loading...

PPT – RNA and Protein Synthesis PowerPoint presentation | free to download - id: 678a8e-ZmU5Z



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

RNA and Protein Synthesis

Description:

RNA and Protein Synthesis Chapter 13 (M) Information Flow Language of DNA is written as a sequence of bases If the bases are the letters the genes are the sentences ... – PowerPoint PPT presentation

Number of Views:11
Avg rating:3.0/5.0
Slides: 43
Provided by: AhmadF2
Learn more at: http://hsfs2.ortn.edu
Category:
Tags: rna | protein | synthesis

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: RNA and Protein Synthesis


1
RNA and Protein Synthesis
  • Chapter 13 (M)

2
Information Flow
  • Language of DNA is written as a sequence of bases
  • If the bases are the letters the genes are the
    sentences
  • Information in DNA is made into Protein
  • RNA ? carries translates the message in DNA to
    protein
  • DNA? RNA ? Protein

3
Flow of information
4
The Central Dogma
  • How do we move information from DNA to proteins?

5
Types of Nucleic Acid
  • DNA (Deoxyribonucleic Acid) - transmits genetic
    information that is passed from one generation
    to the next-double helix
  • RNA (Ribonucleic Acid)


6
Nucleotide
  • Composed of
  • a nitrogen base
  • a pentose sugar
  • a phosphate group

7
Structure of DNA RNA
  • DNA? double strands
  • (a) 5 carbon sugar - deoxyribose
  • (b) phosphate group
  • (c) nitrogenous base adenine (A), guanine (G),
    thymine (T), cytosine (C)
  • AT, GC
  • RNA ?single strand
  • (a) 5 carbon sugar - ribose
  • (b) phosphate group
  • (c) nitrogenous bases - adenine (A), guanine (G),
    uracil (U),cytosine (C)
  • AU, GC

8
RNA-Ribonucleic Acid
  • Single stranded
  • Ribose sugar
  • Four bases? Adenine, Guanine, Cytosine
    Uracil(U)
  • Uracil similar to Thymine and pairs with Adenine

9
Types of RNA
  1. m RNA? transfers the genetic code of DNA in the
    nucleus to the ribosome in the cytoplasm
  2. t-RNA ? transfers amino acids to the ribosome to
    make proteins
  3. r- RNA ? ribosomal RNA

10
Transcription DNA? RNA
  • Construction of RNA along portions of the DNA
    molecule
  • Stages
  • Initiation
  • Elongation
  • Termination

11
Initiation
  • DNA is double stranded and has regions on it
    Promoters (TATA box) where transcription
    starts.
  • DNA is unzipped, bases are exposed
  • RNA Polymerase attaches to the promoter region
    ready to start making RNA

12
Elongation
  1. RNA nucleotides pair with the exposed DNA bases
  2. RNA Polymerase then links the RNA nucleotides
    together to form a chain (mRNA)
  3. As the RNA peels off the DNA chain, DNA strands
    rejoins.

13
Termination
  • When the RNA Polymerase reaches a special base
    sequence of DNA (terminator) which signals the
    end, the RNA Polymerase detaches from the DNA
  • Two other types of RNA tRNA rRNA are made in
    the same way

14
(No Transcript)
15
Editing the RNA Message
  • RNA transcribed in the nucleus is modified before
    it leaves the nucleus as mRNA to be translated.
  • mRNA?
  • Introns? noncoding regions
  • Exons ?the parts that remain will be
    translated, or "expressed
  • RNA Splicing ?joining of the exons after the
    introns are removed

16
RNA Splicing
17
Ribosomes and Protein Synthesis
  • 13.2

18
The Triplet Code
  • DNA stores information to make protein ? 20 AAs,
    functional if order is correct
  • English? 1000s words ? arrangement of 26 letters
  • DNA Code ? sequence of 3 bases (A,T,G,C) ?
    genetic alphabet
  • Start Codon 1, Stop Codons 3

19
The Triplet Code
20
(No Transcript)
21
Translation
  • Process by which mRNA code is read and converted
    into a specific amino acid sequence (protein)
  • Players
  • Ribosomes
  • mRNA
  • tRNA

22
Ribosomes
  • Made of two subunits
  • Large? p-site, A-site
  • Small? m RNA binding site

23
t-RNA
24
Steps in Translation
  1. Initiation
  2. Elongation
  3. Termination

25
Initiation
  • mRNA binds to small subunit of ribosome
  • Initiator tRNA binds to specific start codon on
    mRNA carries the AA Met
  • AnticodonUAC(tRNA)
  • Codon AUG (mRNA)
  • Large subunit binds to the small? functional
    ribosome

26
Initiation
27
Initiation
28
Elongation
  • Codon Recognition incoming tRNA with an AA
    attached pairs with the mRNA codon on the
    A-site
  • Peptide bond formation a bond is formed between
    the AA or peptide on P-site AA on the
    A-site
  • Translocation P-site tRNA moves out. A-site
    tRNA w/polypeptide chain moves to P-site

29
Ribosome with mRNA and tRNA
30
Figure 17.18 The elongation cycle of translation
31
Termination
  • Process continues till a stop codon is reached
  • Process is terminated.
  • Stop Codons UAA, UAG, UGA

32
Termination
33
Mutations in Genes
  • Ch 13.3

34
Mutation
  • A change in the nucleotide sequence of DNA
  • Can involve large sections of the DNA or just a
    single nucleotide pair (Point mutations)
  • Types
  • Base Substitution
  • Base Deletion
  • Base Insertion

35
Base Substitution
36
Base Substitution
37
Base Insertion/Deletion
  • Is usually more disastrous than the effects of
    base substitutions
  • RNA is read as a series of triplets, thus adding
    or removing nucleotides will affect all
    nucleotides downstream.
  • Will result in a different , non working protein

38
(No Transcript)
39
Causes of Mutations
  • May occur when errors are made during DNA
    replication
  • When errors are made during chromosome crossovers
    in meiosis.
  • Physical or chemical agents ? mutagens

40
Mutagen
  • Physical mutagen ? high-energy radiation? X-rays
    and ultraviolet light.
  • Chemical mutagen ? chemicals that are similar to
    normal DNA bases but cause incorrect base-pairing
    when incorporated into DNA.

41
Mutations Good or Bad
  • Harmful
  • Cancers
  • Sickle cell disease
  • Beneficial
  • Chemical resistance
  • Plants ? polyploidy

42
Mutations Good or Bad
  • Mutations ? genetic diversity
  • May be beneficial? tiger swallowtail butterfly?
    mutations cause a change in color? predators
    confuse it with w/ black swallowtail which is
    poisonous and avoid it
About PowerShow.com