Jackson High School
Biology
EOC Review
Section 3 DNA/RNA, DNA Replication, Protein Synthesis
DNA & RNA
Nucleotides DNA
Nucleic acids are made up of Nucleotides Macromolecule = Nucleic Acid
Monomer = Nucleotide
Each nucleotide is made of a phosphate group, a sugar molecule, and a nitrogen base Example of Nucleic Acids: DNA & RNA DNA stands for
deoxyribonucleic acid
DNA stands for
ribonucleic acid
Base )
The shape of DNA is a double helix Composed of nucleotides
The sides are made of pentose sugar and the center is made of nitrogen bases bonded together by weak hydrogen bonds
Nitrogen Bases:
Adenine
Thymine
Guanine
Cytosine
Never leaves the nucleus
Controls production of all proteins
Sy
DNA coiled into chromosomes in the nucleus
Tiny sections of DNA are called genes
Sequence of bases determines sequence of
amino acids.
De eC tc,
DNA Base Pairs
A always pairs with T G always pairs with C RNA RNA Base Pairs
RNA is single-stranded
Has a backbone made of alternating sugar
(ribose) and phosphate groups. Attached to
teach sugar is one of the following bases:
. Adenine
° Uracil ° Guanine Cy
t
o
si
n
e
N
D
.
. L
eaves
n
u
A always pairs with U and G always pairs with C.
t
he
c
leus
DNA v s. RNA
Nucleotides:
DNA RNA Nucleotides:
* Adenine (A) --- Thymine (T) * Guanine (G) --- Cytosine (C) Base Pairs:
A pairs with T
G pairs with C
Structure:
* double-stranded (double-helix)
Adenine (A) --- Uracil (U)
Guanine (G)} --- Cytosine (C)
Base Pairs:
A pairs with U
G pairs with C
* There isno Tin RNA - it contains the nitrogen base Uracil (U) instead
Structure:
e Single-stranded 38
DNA g RNA
Genetic Code
* The genetic code is universal to all life which tells use that everything is related/shares a common ancestor. * The genetic code is made up of codons, which are nucleotides arranged in groups of 3. * Each codon codes for one specific amino acids.
* Variations in the genetic code are caused by mutations which can alter the protein sequence and can then lead to variation within a species.
ae ING l Mutations
Original DNA Strand IeMmalalelclciciclalalc! DID
|caujlucaliaca]fuual
Original DNA Strand GITHATAlGliciiclicilc|tallalic! caAu|juce||acalluua DODD
Original DNA Strand GIT IATA Giiciiciiciciallajic)
Original DNA Strand ITA Alieliciiciiciic}laltalic]
Missense Mutation
4>
Nonsense Mutation A
ENN A
jcau|luca||aaal
GED
Deletion Mutation
CIICHICIICILAIATLCILA!
. Change in the genetic code.
° Passed from one cell to new cells.
. Transmitted to offspring if mutation occurs in sex cells.
Gene Mutation: change in a single gene; point, substitution, insertion, and deletion.; occurs during DNA replication.
* Caused by errors during DNA replication, environmental factors, or inherited from parents. + Examples of gene mutations: genetic disorders, changes in physical traits such as eye color, variation in protein function, and increased risk of disease such as cancer.
Chromosome mutation: change in the structure or number of chromosomes. (examples: deletion, duplication, inversion, and translocation mutations). * Mutations can be spontaneous, caused by
environmental agents (radiation, chemicals, etc.}, or inherited from parents. )
Examples of chromosomal mutations: down syndrome, turner syndrome, etc.)
Duplication Deletion Insertion Inversion Translocation AA oA AA Ba a
<0
ee Cl A \J Wei We We ly ie
[cau}luca|laca]fuuc
4 jcau|luce|[acu]fuau]
<I
B
>
GHB
CDAD] Original DNA Strand
Insertion Mutation
a3 7 \J [4NJ ly W wigi] \W
* Gene Mutations and Phenotypic Effects: * Silent Mutation: Most mutations have no phenotypic (physical) effect.
SIT HaAlAliciicliciiciiciallalic! ODD
jcaujjucea|laaa|[uual
Al enDiciicltchal
e
44> jcau|fuca|[acal[auu] ODED
Occasionally, mutations can provide an advantage to an organism, allowing for adaptation and evolution.
* Germline Mutations: mutations present in soerm or egg (sex cells/gametes). Can be inherited. * Somatic Mutations: occurs in non-sex cells (body cells). Cannot be inherited. Mutationis 39 in the form of a tumor.
DNA REPLICATION & CENTRAL DOGMA
DNA Replication
* DNA must be copied. This process is called replication.
* DNA replication = DNA > DNA
+ At the end of DNA replication, you are left with 2 identical strands of DNA, each consisting of one original strand of DNA and a complimentary strand of DNA. (it9s like we put our DNA through a copy machine.}
* Takes place in the nucleus of eukaryotes.
* Original strand 4 from the DNA that was split during replication
* Complimentary strand 4 the new strand that was created when the base pairs were filled in.
Original
(template) DNA |O riginal Strand |
Original
EE
Ie
=> |
>|
Polymerase DNA CD
(template
ion : = Complimentary Strand
Repl
i
c
a
t
F
o
r
k
Replication Steps 4 Semiconservative Model:
1. Helicase unwinds and separates the original DNA double helix by breaking the hydrogen bonds between the base pairs, creating a replication fork/two single strands of DNA.
2. Each single strand of DNA acts as a template to create the new complimentary strand of DNA. 3. DNA polymerase (an enzyme) adds the nucleotides for the complimentary strand of DNA according to the base-pair rules.
4. The replication fork/2 strands of DNA meet, completing the replication process. Semiconservative Model: the process of DNA replication that creates 2 identical copies of the original DNA molecule. Each copy has one original strand and one new strand.
Central Dogma
The flow of genetic information within a biological DNA Replication:
system. Describes how DNA is copied and used to * The process of making identical copies of DNA make proteins * Occurs when double-stranded DNA molecules is unzipped and copied
plication
*DNAto DNA Transcription:
t fis J { * The process of making RNA copies of genes. | * Converts DNA into messenger RNA (mRNA). 4 ")
Transcription ;
Translation:
lo sO RNG J | * The processes for decoding mRNA into amino acids, which then form proteins.
. Produces proteins that are essential for life | Translation functions.
<RNA to Protein
. J
40
PROTEIN SYNTHESIS
Protein Synthesis:
The biological process by which cells create protein. Consists of transcription and translation. Transcription: (DNA > RNA)
* Takes place in the nucleus.
* The process of converting DNA into RNA (mRNA).
° Made from one strand of DNA.
Original DNA Strand: mRNA Strand:
ATG-4 GAC 4 AAC - TTA UAC 4 CUG 4 UUG 4 AAU
-, W EW LJ W Le
ALI G TAMA GE UROA R T aoe
mRNA shor...
A Original DNA Strand Translation: (RNA > Protein)
Process of translating mRNA to protein.
Takes place in the ribosome.
To do this, you must break the RNA strand into codons (groups of 3).
The use of a codon chart to translate RNA into a protein is required. M i
Seconel A
MRNA Strand: mRNA Strand:
Base
UAC 4 CUG 4 UUG 4 AAU Tyr 4 Leu 4 Leu - Asn
How to Use a Codon Chart: In order to to translate an RNA sequence into
Base First
Phe | Ser | Tyr
Phe | Ser | Tyr | Cys Leu | Ser
Leu | Ser
Leu | Pro | His | Arg Leu | Pro | His | Arg Leu | Pro | Gin | Arg Leu | Pro | Gin | Arg
lle The | Asn | Ser lle Thr | Asn | Ser < lle Thr | Lys | Arg Mel | Trhr | Lys | Arg
Val | Ala | Asp | Gly Val | Ala | Asp | Gly Vol | Ala | Glu | Gly Val | Ala | Glu | Gly
proteins you must...
1. Break the RNA sequence into codons ¥ Example: AAC - GGA 4UCA4UUU
v If your genetic sequence contains the letter T, that means it is a DNA sequence. You cannot use DNA sequences in a
codon chart. This means you you must transcribe your DNA sequence into RNA first.
2. Take each codon and put it into the codon chart.
3. By putting your codons into the codon char, it will translate your codons into proteins. ¥ Example: Asn 4- Gly - Ser - Phe 41
DNA, PEPLICATION & PROTEIN SYNTHESIS KNOWLEDGE CHECK! Question #1 Question #2
Which of the following correctly describes how nitrogenous bases pair in a DNA molecule? A) Adenine (A) pairs with cytosine (C), and guanine (G) pairs with thymine (T).
B) Thymine (T) pairs with guanine (G), and cytosine (C) pairs with adenine (A).
C) Adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).
D) Cytosine (C) pairs with uracil (U), and thymine (T) pairs with adenine (A).
A scientist analyzes a DNA strand and identifies the following sequence:
TACGGAATGCCCTTIIGGA
How many codons does this sequence contain? A) 4
B) 5
C) 6
D) 9
Question #3 Question #4
During DNA replication, an enzyme proofreads the new DNA strands to correct errors. Why is this proofreading process important?
A) It ensures that no mutations ever occur in the DNA. B) It helps prevent harmful genetic changes that could lead to diseases.
C) It allows DNA to replicate in multiple directions at the same time.
D) It eliminates the need for RNA during protein synthesis.
Which of the following statements correctly describes how DNA strands are replicated?
A) Each new DNA molecule consists of two entirely new strands of DNA.
B) DNA replication occurs randomly throughout the cell cycle.
C) DNA polymerase adds nucleotides to the new strand using complementary base pairing. D) The process results in one single-stranded DNA molecule instead of two double helices.
Question #5 Question #6
During DNA replication, a DNA strand with the sequence ATCGGATC is being copied. What will be the complementary strand that is formed? A) TAGCCTAG
B) UAGCCUAG
C}) ATCGGATC
D) GCTAGGCT
Scientists compare the DNA sequences of different species fo determine their evolutionary relationships. If two species have a high percentage of identical DNA sequences, what does this most likely indicate? A) They evolved in the same environment but are not genetically related.
B) They developed similar traits by chance through random mutations.
C) They have no evolutionary connection and their similarities are purely coincidental.
D) They share a recent common ancestor and are closely related.
Question #7 Question #8
During DNA replication, a new strand is formed based on the sequence of the original DNA strand. If the original strand is:
ATCGGTAAC
What will be the complementary daughter strand?
A) TAGCCATIG
B) UAGCCAUUG
C) GCTAACGGT
D) ATCGGTAAC
A scientist wants to stop a cell from producing a specific protein. Which of the following would be the most effective way to prevent the protein from being made?
A) Block the DNA from being replicated before cell division.
B) Prevent mRNA from being transcribed from DNA. C) Increase the number of ribosomes inside the cell. D) Remove amino acids from the cell's environment.
DNA, REPLICATION & PROTEIN SYNTHESIS KNOWLEDGE CHECK!
Question #9 Question #10
During transcription, a DNA strand is used as a During DNA replication, a new strand is formed based template to create a complementary RNA strand. If on the sequence of the original DNA strand. If the the DNA sequence is: original strand is: TAAGCACCTGAA TACGGCATC What will be the complementary daughter strand? What will be the corresponding mRNA strand?
A) ATGCCGTAG A) AUUCGUGGACUU
B) UACGGCAUC B) ATTGCAUACCAA
C) AUGCCGUAG C) GCTAACGGT
D) TACGGCATC D) ATTCGTGGACTI
Question #11 Question #12
A DNA strand with the sequence GCTTAGGCCA is A scientist is examining a DNA molecule during transcribed into MRNA. What will be the correct mRNA | replication. If one strand of the DNA has the sequence? sequence:
A) CGAATCCGGT GCTTAGGCCA
B) GCTTAGGCCA What will be the newly formed complementary C) UCGUUAGGCU strand2
D) CGAAUCCGGU A) GCTTAGGCCA
B) CGAATCCGGT
C) UCGUUAGGCU
D) AGGCCGAATC
Question #13
A strand of mRNA has the following sequence:
AUG GCU ACA UGA Seconel Base Using a codon chart, what is the correct sequence of
amino acids produced?
A) Methionine - Alanine - Threonine - Stop
U Cc A G
B) Alanine - Threonine - Methionine - Stop re eer ul on Base
C) Methionine - Glycine - Serine - Stop Leu | Ser | Stop | Stop D) Start - Glycine - Threonine - Alanine Leu | Ser | Stop | Tro
leu | Pro | His | Arg Question #14 Pro | His | Arg
If a cell transcribes the following mRNA strand: CCG UA GGA UAG
What would be the correct sequence of amino acids?
First
A) Arginine - Valine - Aspartic Acid - Stop Val | Ala | Asp | Gly B) Proline - Lysine - Glycine - Stop cg | Ye
C) Proline - Leucine - Glycine - Stop
D) Leucine - Proline - Arginine 4 Stop
Question #15
Which of the following correctly describes the main difference between transcription and translation? A) Transcription takes place in the ribosome to assemble amino acids, while translation occurs in the nucleus to copy DNA.
B) Transcription occurs in the nucleus and converts DNA into mRNA, while translation occurs in the cytoplasm and converts mRNA into a protein.
C) Transcription uses ribosomes to read mRNA and build proteins, while translation creates mRNA using DNA as a template.
D) Transcription and translation are the same process, just occurring in different parts of the cell.