Module 2 The Flow of Genetic Information in the Cell Flashcards
What are the Three main steps in the flow of genetic information also known as ____
Central Dogma of Biology
Replication (DNA - DNA)
Transcription (DNA encodes RNA)
Translation (RNA encodes proteinsProtein)
____ The process by which a cell makes an identical copy of its genome before it divides.
The _____ in the DNA carries the genetic code
DNA Replication
Sequence bases
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 ____.
Amino acids
Nucleus
Ribosomes
Cytoplasm
Rough Endoplasmic Reticulum (RER)
____ carries the info from DNA in the nucleus during (____) to a ____ in the ____ that the helps assemple the protein during (_____)
RNA
Transcription
Ribosome
Cytoplasm
Translation
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
one nucleotide
three mRNA nucleotide
one amino acid
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
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
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
mRNA
tRNA
mRNA & Amino Acids
rRNA
snRNA
snoRNA
miRNA
siRNA
IncRNA
____ 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 ____
DNA
Adenine
Cytosine
Guanine
Thymine
RNA
Thymine
Uracil
DNA
Helix:
Location:
Sugar:
Main type(s):
DNA
Helix: Double-stranded
Location: Nucleus
Sugar: Deoxyribose
Main type(s): B-form DNA
RNA
Helix:
Location:
Sugar:
Main type(s):
RNA
Helix: Single-stranded
Location: Nucleus & Cytoplasm
Sugar: Ribose
Main type(s): mRNA, rRNA, tRNA
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
Topoisomerase
Initiation, Elongation, Termination
Telomeres
1 x 10 ^-8 mistakes / base
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
Semiconservative Model
Conservative Model
Dispersive Model
___________________
Semiconservative
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
Meelson and Stahl Experiment
Heavy nitrogen (15 N)
Light nitrogen (14 N)
40 min
_____ Complementary strand runs in opposite direction
Bonding in DNA is through:
____ for bases
____ for backbone
Anti-parallel strands
Hydrogen bonds - bases
Covalent phosphodiester bonds - backbone
_____ 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)
E. coli
Eukaryotic
Three general features of chromosomal replication (3)
DNA Replication is semiconservative
DNA Replication is Bidirectional
DNA Replication begins at Specific Chromosomal Sites
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 ____
Origin of Replication
Replication origins
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
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
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”
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
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
1 per every 100 000 nucleotides
120 000 mistakes every division
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:
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
