Std.6 DNA and Protein Synthesis ReviewDescribe the structure of DNA and summarize the process of DNA replication.

Identify and describe the steps in proteins synthesis (hint: transcription & translation)

Name the 4 nitrogenous bases for DNA:_______________________

________________________________________________________

DNA base Pairing rules: adenine (A) → ______________________

(T); and _________________________(G) → cytosine (C)

Name the 3 types of RNA: __________________________________

RNA base pairing rules: adenine (A) → _____________________

(U); and guanine (G) → _________________________ (C)

Define DNA mutation: ___________________________________

How can a mutation affect a protein: _________________________

_______________________________________________________

Question Analysis: Identify key terms/info. in each question and provide a responseThe mRNA strand of mRNA containing the repeating sequence AAGAAGAAGAAG could code for amino acid sequences?

___________ - ___________ - ___________ - __________

The below sequence of DNA is part of a gene. How many amino acids are coded for by this segment?

5’ ATCAGCGCTGGC

A scientist puts nucleotide chains of UUUUUU in a test tube under conditions allowing protein synthesis. Soon the test tube is full of polypeptide chains composed of only the amino acid phenylalanine. What does this experiment indicate?

Semi-conservative replication of DNA refers to the idea that…

What would be the base sequence for mRNA for the following DNA sequence: ACAGTGC

mRNA → ______________________

One human disease is caused by a change in one codon in a gene from GAA to GUA. This disease is the result of a:

__________________________________

Although there are a limited number of amino acids, many different types of proteins exist because:

This segment of DNA below has undergone a mutation in which three nucleotides have been deleted. A repair enzyme would replace them with what?

5’ GTA_ _ _ AA 3’ → Replacement =3’ CATGCATT 5’ ____ ____ ____

Mutations within a DNA sequence are (write correct letter) _____

a. natural processes that produce genetic diversity. b. natural processes that always affect the phenotype. c. unnatural processes that always affect the phenotype. d. unnatural processes that are harmful to genetic diversity.

Std.6 DNA Study GuideI. DNA Structure – double stranded helix (twisted)

o Sugar phosphate backboneo Location: nuclus

Monomers (subunits) = nucleotides Nucleotide – 3 parts:

o 5 carbon sugar (deoxyribose)o Phosphate Groupo Nitrogenous Base

DNA Base Pairing Rules:o Adenine – Thymine → A - To Guanine – Cytosine → G – C

II. DNA Replication Replication = copying of DNA

o Semiconservative Replication1) Enzyme (helicase) “unzips” DNA2) Each original strand serves as a template3) Enzyme (DNA polymerase) attachs nucleotides following base paring rules(A-T & C-G)4) DNA polymerase “proof reads” strands for errors

End result: 2 complete identical DNA molecules

III. RNA & Protein Synthesis RNA = Single stranded Does not use nitrogenous base Thymine

o New base = UracilRNA Base Pairing Rules:

o Adenine – Uracil → A - Uo Guanine – Cytosine → G – C

3 Types of RNA: mRNA, tRNA, & rRNASteps to Protein Synthesis: 1 Gene codes for 1 protein 2 Parts to Protein Synthesis: Transcription & Translation

Transcription1) Single gene on DNA opens2) mRNA made from gene template following RNA base paring rules3) mRNA carries “instructions” to build protein to the ribosome

Translation4) mRNA is read in series of 3 nucleotides at a time → codon (aau,

gcg, agc, etc)5) tRNA brings correct amino acids to ribosome to build protein

IV. Mutations Random changes in DNA sequence

o Results from “mistakes” in replication of DNA Mutations can involve single genes or entire chromosomes

o Examples: point mutation & frame shift mutations