Unit 5 DNA RNA Proteins DNA RNA Proteins

  • Slides: 30
Download presentation
Unit 5 DNA RNA Proteins

Unit 5 DNA RNA Proteins

DNA/ RNA/ Proteins Word Meanings • Deoxy - a molecule containing less oxygen than

DNA/ RNA/ Proteins Word Meanings • Deoxy - a molecule containing less oxygen than another • ribose - A pentose sugar, C 5 H 10 O 5 • Complementary – to “match up” • Subunit – a piece or small part of a larger unit. • replication – the act of duplicating, copying, or reproducing • transcription – the act or process of rewriting in a different script. • translation – to rewrite in a second language having the same meaning as the original source.

I. DNA: Deoxyribonucleic Acid i. Complete instructions for manufacturing all the proteins for an

I. DNA: Deoxyribonucleic Acid i. Complete instructions for manufacturing all the proteins for an organism. (which determine all your other characteristics) ii. The “recipe” for life! iii. structure of DNA proved that it was in fact the molecule of heredity iv. Analogy: 1000 textbooks= all the info (DNA/genes) of 1 single organism

a. Structure i. Watson & Crick 1. proposed that DNA is made of chains

a. Structure i. Watson & Crick 1. proposed that DNA is made of chains 2. nucleotides held together by nitrogenous bases (teeth of zipper) 3. proposed that DNA is shaped like a long zipper that is twisted into a coil like a spring → helix 4. DNA is a double helix

b. Nucleotide = monomer of DNA i. Subunits of DNA ii. 3 parts 1.

b. Nucleotide = monomer of DNA i. Subunits of DNA ii. 3 parts 1. phosphate group 2. simple sugar: deoxyribose 3. nitrogenous base a) b) c) d) A= adenine G= guanine C=cytosine T=thymine Ø Complementary base pairs → A-T & C-G iii. Phosphate groups & Deoxyribose sugar form backbone of DNA iv. Chargaff’s Rule: i. ii. The number of Adonines = number of Thymines The number of Guanines = number of Cytosines

The Base pairing rules: A binds to T with 2 Hydrogen bonds and G

The Base pairing rules: A binds to T with 2 Hydrogen bonds and G binds to C with 3 Hydrogen bonds

DNA in Eukaryotes & Prokaryotes • Eukaryotes – Eukaryotic DNA is in the form

DNA in Eukaryotes & Prokaryotes • Eukaryotes – Eukaryotic DNA is in the form of chromosomes – Replication occurs in the nucleus – Eukaryotes can begin self-replicating at any origin on the chromosome – Self-replicates in a five to three prime direction • Prokaryotes – Prokaryotic DNA is in the form of a ring – Replication occurs in the cytoplasm because the DNA is floating free in the cell – has to begin self-replicating at the Origin of Replication. – Self-replicates in a five to three prime direction

The DNA Replication Process 3. The enzyme Primase adds a Primer at the replication

The DNA Replication Process 3. The enzyme Primase adds a Primer at the replication fork to begin the replication process (A primer is made of RNA nucleotides that will attach to the DNA strand) 4. DNA polymerase III is an enzyme that joins individual nucleotides to the growing DNA strand to produce a new strand of DNA that is complementary to the original DNA strand. • New bases are added in a 5’ to 3’ and according to base pairing rules: – A with T – G with C

The DNA Replication Process Replication begin at the origin. (different places for eukaryotes &

The DNA Replication Process Replication begin at the origin. (different places for eukaryotes & prokaryotes) 1. Unzipping of the DNA molecule occurs by the action of the enzyme Helicase (this enzyme breaks the Hydrogen bonds between nitrogenous bases) 2. Helicase creates a replication fork and provides the two original strands as templates to create two new strands by means of semi-conservative replication. •

The DNA Replication Process 5. DNA polymerase I removes the primer and replaces it

The DNA Replication Process 5. DNA polymerase I removes the primer and replaces it with DNA nucleotides to complete the self-replicating process. • The primer is made of RNA nucleotides so those can’t be left in the DNA molecule • Two identical DNA molecules result. This is Semi. Conservative Replication (Produces two copies of DNA that each contains one strand of the original strands and one new strand)

The DNA Replication Process • DNA is composed of two anti-parallel strands which are

The DNA Replication Process • DNA is composed of two anti-parallel strands which are self -replicating at the same time in a 5’ to 3’ direction – Leading strand – being produced continuously and being replicated towards the replication fork – Lagging strand – being produced discontinuously and being replicated away from the fork

V. RNA a. b. c. Ribonucleic Acid Single stranded RNA is a special copy

V. RNA a. b. c. Ribonucleic Acid Single stranded RNA is a special copy of DNA used to make proteins. Single RNA strand

a. RNA Nucleotides (monomer) i. Subunit of RNA ii. 3 parts: 1. phosphate group

a. RNA Nucleotides (monomer) i. Subunit of RNA ii. 3 parts: 1. phosphate group 2. simple sugar= ribose 3. nitrogenous base a. U= uracil (Replaces T) b. A= adenine c. G= guanine d. C=cytosine Ø Complementary base pairs → A-U & C-G Ø Phosphate group and ribose make up backbone of RNA

c. 3 Types of RNA i. m. RNA → messenger Ø carries a copy

c. 3 Types of RNA i. m. RNA → messenger Ø carries a copy of the DNA’s instructions (code) for the creation of proteins.

ii. r. RNA → ribosomal Ø Makes up ribosomes - structures where proteins are

ii. r. RNA → ribosomal Ø Makes up ribosomes - structures where proteins are assembled. iii. t. RNA → transfer Ø carries amino acids to the ribosome and matches them to the coded m. RNA message.

b. Transcription (DNA→RNA) i. RNA copies are created from DNA in the nucleus 1.

b. Transcription (DNA→RNA) i. RNA copies are created from DNA in the nucleus 1. RNA polymerase is an enzyme that uses only one side of DNA as a template to create a single strand of RNA. 2. New bases are added to a growing m. RNA strand in a 5’ to 3’ direction. 3. base pairing rules: (A with U, G with C, T with A). Ex. DNA = ATTCGCATT RNA = UAAGCGUAA

e. Amino Acids i. Basic building blocks of proteins carried by t. RNA ii.

e. Amino Acids i. Basic building blocks of proteins carried by t. RNA ii. Codon: 3 bases on m. RNA code for 1 amino acid iii. 64 different combinations can create 20 different amino acids.

d. Translation (m. RNA → proteins) i. Converting m. RNA into amino acids then

d. Translation (m. RNA → proteins) i. Converting m. RNA into amino acids then into a protein 1. To begin Translation the r. RNA must binds to the m. RNA 2. translation begins at the start codon[AUG]-(three bases in a row) on the m. RNA. 3. t. RNA contains an anti-codon that binds to the m. RNA’s codon and carries one kind of amino acid.

4. The amino acids bond together and stop when a “stop codon” is reached.

4. The amino acids bond together and stop when a “stop codon” is reached. 5. The newly formed polypeptide (protein) is then released.

What does a Protein look like?

What does a Protein look like?

The Central Dogma • DNA→ m. RNA→ Protein • The creation of m. RNA

The Central Dogma • DNA→ m. RNA→ Protein • The creation of m. RNA from DNA is called Transcription • The creation of a protein from m. RNA is called Translation

Comparing DNA and RNA DNA Type of Sugar Number of Strands Nitrogenous Bases Location

Comparing DNA and RNA DNA Type of Sugar Number of Strands Nitrogenous Bases Location in Cell RNA

III. Mutations i. Any changes in the DNA sequences This could be: ii. 1.

III. Mutations i. Any changes in the DNA sequences This could be: ii. 1. 2. 3. 4. iii. Deletion of bases Duplicating bases Ceratain bases changing places New bases being inserted where they do not belong. Mutations can result in: a. Genetic diseases b. Cancer c. New genetic traits d. No harm at all

 • Genetic Disorders caused by mutations to the DNA: Disorder Color blindness Cri

• Genetic Disorders caused by mutations to the DNA: Disorder Color blindness Cri du chat Cystic fibrosis Down syndrome Duchenne muscular dystrophy Haemochromatosis Haemophilia Klinefelter syndrome Sickle-cell disease Tay–Sachs disease Turner syndrome Mutation Point Deletion Point Extra Chromosome 21 Chromosome X 5 7 21 Deletion X Point Extra X-Chromosome (males) Point Missing one X-Chromosome 6 X X 11 15 X

IV. Manipulating DNA – How do we manipulate DNA? • We can literally cut

IV. Manipulating DNA – How do we manipulate DNA? • We can literally cut the DNA into pieces. – – – This is done through the use of proteins known as restriction enzymes They cut the DNA at certain Base Pair sequences We use the cut up DNA for all sorts of things. • • Paternity test Criminal Investigation • • Genetic Engineering Cloning

 • Paternity Test and Criminal Investigations – Cut up fragments of certain DNA

• Paternity Test and Criminal Investigations – Cut up fragments of certain DNA segments are put into a gel electrophoresis. – Depending on how big the segment of DNA, the further down the gel a fragment of DNA will move. – Doctors and scientist can then compare one persons DNA to another persons to see if they’re related.

 • Genetic Engineering – Cut up fragments of DNA segments with specific genes

• Genetic Engineering – Cut up fragments of DNA segments with specific genes can be added to the DNA of a fertilized egg. • This can give rise to organisms with new traits. • Ex. Mice that can glow Here the gene for insulin is being put into the plasmid of a bacterial cell. The bacteria will now produce insulin for human use.

 • Cloning – Theoretically, any organism can be cloned to make a genetically

• Cloning – Theoretically, any organism can be cloned to make a genetically identical organism. – This is done by a process called Nuclear Transfer 1. Extract the nucleus of an unfertilized egg. 2. Insert a nucleus (DNA) from a cell of the organism you want to clone. 3. Cause the egg cell with the novel nucleus to start dividing by stimulating the egg with a shock of electricity. 4. After the embryo grows for a few days it is placed inside a serogate mother and allowed to develop there until birth. These two cats are clones: But they look different. This is because different genes on the same DNA can be activated by the different environments the organism grew up in.