Module 2 The Flow of Genetic Information in the Cell

Question 1

What are the Three main steps in the flow of genetic information also known as ____

Answer 1

Central Dogma of Biology

Replication (DNA - DNA)

Transcription (DNA encodes RNA)

Translation (RNA encodes proteinsProtein)

Question 2

____ The process by which a cell makes an identical copy of its genome before it divides.

The _____ in the DNA carries the genetic code

Answer 2

DNA Replication

Sequence bases

Question 3

Instructions for making proteins with the correct sequence of ____ are encoded in DNA

DNA is found in chromosomes and in eukaryotic cells, chromosomes always remain in the ______

Proteins are made at ____ in the ____ or on the ____.

Answer 3

Amino acids

Nucleus

Ribosomes
Cytoplasm
Rough Endoplasmic Reticulum (RER)

Question 4

____ carries the info from DNA in the nucleus during (____) to a ____ in the ____ that the helps assemple the protein during (_____)

Answer 4

RNA
Transcription

Ribosome
Cytoplasm
Translation

Question 5

When copying DNA to RNA, ____ is added to the mRNA strand for every nucleotide in the DNA

When translating to protein, ____ corresponds to ____ in the polypeptide sequence.

Ultimately, this means that translation to protein is still systematic and colinear

Answer 5

one nucleotide

three mRNA nucleotide

one amino acid

Question 6

DNA REPLICATION/SYNTHESIS:

Each strand of existing DNA act as a template for ____.

Overview of DNA Replication:

a) ______
Each base is paired by hydrogen bonding with its specific partner, A - T and G - C

b) _____

c) _____
Determines the order of nucleotides along a new, complemetary stransd

d) ______
to form the sugar phosphate backbones of the new strand. Each “___” DNA molecule consists of one parental strand

Answer 6

Replication

a) Two complementary strands of DNA for parent molecule

b) Separation of the two DNA strands

c) Each strand becomes a template

d) Nucleotides are connected

Question 7

Types of RNA produced in cells:

Encodes proteins

Acts as an adaptior between ___ and ____

Forms the Ribosome

Functions in various nuclear processes (splicing)

Facilitates chemical modification of RNAs

Regulates gene expression

Silences gene expression

Also Regulates Gene Expression

Answer 7

mRNA

tRNA
mRNA & Amino Acids

rRNA

snRNA

snoRNA

miRNA

siRNA

IncRNA

Question 8

____ Contains genetic instructions that allow organisms to grow and function. Includes these nitrogenous bases(4)

____ Executes the insructions and synthesizes proteins. Includes the same nitrogenous base except: _____ because it has ____

Answer 8

DNA
Adenine
Cytosine
Guanine
Thymine

RNA
Thymine
Uracil

Question 9

DNA

Helix:
Location:
Sugar:
Main type(s):

Answer 9

DNA

Helix: Double-stranded
Location: Nucleus
Sugar: Deoxyribose
Main type(s): B-form DNA

Question 10

RNA

Helix:
Location:
Sugar:
Main type(s):

Answer 10

RNA

Helix: Single-stranded
Location: Nucleus & Cytoplasm
Sugar: Ribose
Main type(s): mRNA, rRNA, tRNA

Question 11

KEY CONCEPTS:

_____ catalyze changes in supercoiled state of DNA

DNA replication has three distinct phases (___, ____, and ____) the last one is different at ____ of eukaryotic chromosomes

DNA replication is very accurate since it allows _____ mistakes/base

Answer 11

Topoisomerase

Initiation, Elongation, Termination
Telomeres

1 x 10 ^-8 mistakes / base

Question 12

3 Proposed Models of Replication:

Our DNA actually is ______ which means that each strand of the double helix parent DNA serve as a template to male two new daughter strands

Answer 12

Semiconservative Model

Conservative Model

Dispersive Model
___________________

Semiconservative

Question 13

Experiment used to confirm which model is the right one ____

Bacteria cultured in medium containing ____ (___)

Bacteria transferred to medium containing ____(___)

Centrifuge DNA sample after ____ min

Answer 13

Meelson and Stahl Experiment

Heavy nitrogen (15 N)

Light nitrogen (14 N)

40 min

Question 14

_____ Complementary strand runs in opposite direction

Bonding in DNA is through:

____ for bases

____ for backbone

Answer 14

Anti-parallel strands

Hydrogen bonds - bases

Covalent phosphodiester bonds - backbone

Question 15

_____ replicates its DNA at a rate of 1000 nucleotides per second with less than one error in a billion nucleotides

____ replication proceeds at a rate ranging from 500 to 5000 nucleotides per minute at each replication fork (100 per nucleotides per second)

Answer 15

E. coli

Eukaryotic

Question 16

Three general features of chromosomal replication (3)

Answer 16

DNA Replication is semiconservative

DNA Replication is Bidirectional

DNA Replication begins at Specific Chromosomal Sites

Question 17

Replication begins at an ____ then the double helix unwings in opposite directions, replicating DNA both ways away from two replication forks

DNA synthesis is initiated at special regions called ____

Answer 17

Origin of Replication

Replication origins

Question 18

Summary of DNA Replication

1 _____ unwind the parental double helix

2 _____ stabilize the unwound parental DNA

3 ____ is synthesized continuously in the 5’ - 3’ direction by ____

4 _____ is synthesized discontinuously.

_____ synthesizes a short ____ which is extended by a ____ to form an ____

5 After the ____ is replaced by DNA, ____ joins the ____ to the growing strand

Answer 18

1 Helicase unwind the parental double helix

2 Single-strand binding proteins stabilize the unwound parental DNA

3 The leading strand is synthesized continuously in the 5’ - 3’ direction by DNA polymerase

4 The Lagging Strand is synthesized discontinuosly.

Primase synthesizes a short RNA primer which is extended by a DNA polymerase to form an okazaki fragment

5 After the RNA primer is replaced by DNA, DNA ligase joins the okazaki fragments

Question 19

DNA Replication: Enzymes involved (10)

____(DNApol clamp loader)
____ unwinds
____ stabilizes
____ supercoiling , chromosomal DNA in bacteria. Prevents tangling upstream (____)

DNA polymerase I -
DNA polymerase II-
DNA polymerase III -

_____ creates RNA primers
_____ binds okazaki fragments “spot welder”

Answer 19

Initiator proteins

Helicase

Single-strand binding proteins

topoisomerase I & II (DNA gyrase)

________________

repairs, removes RNA primers and replaces DNA nucleotides

cleans up okazaki fragments

Main or primary polymerase, builds new DNA to existing strands of DNA

________________

DNA primase
DNA ligase

Question 20

Enzymes do make mistakes at a rate of about 1 per every ____ nucleotides

considering 6 billion base pairs in each diploid cell, it would be ____ mistakes every time a cell divides

Answer 20

1 per every 100 000 nucleotides

120 000 mistakes every division

Question 21

Modes of Replication:
Individual units of replication are called _____ reach contains a ____

TEMPLATE:
BREAKAGE:
REPLICONS:
DIRECTION:
PRODUCTS:

1) _____
Common type of replication that occurs in circular DNA (E coli)
TEMPLATE:
BREAKAGE:
REPLICONS:
DIRECTION:
PRODUCTS:

2)_____
Takes place in some viruses and ecoli F factor
TEMPLATE:
BREAKAGE:
REPLICONS:
DIRECTION:
PRODUCTS:

3)____
Replication takes place simultaneously from thousands of origins
TEMPLATE:
BREAKAGE:
REPLICONS:
DIRECTION:
PRODUCTS:

Answer 21

Replicons
Replication origin

Theta replication

TEMPLATE: circular
BREAKAGE: no
REPLICONS: 1
DIRECTION: both
PRODUCTS: two circular molecules

Rolling-cycle replication

TEMPLATE: circular
BREAKAGE: yes
REPLICONS: 1
DIRECTION: Unidirectional
PRODUCTS: 1 circular, 1 linear

Linear-eukaryotic replication

TEMPLATE: linear
BREAKAGE: no
REPLICONS: many
DIRECTION: bidirectional
PRODUCTS: 2 linear molecules