DNA & RNA structures

DNA replication

The cell copies its DNA before it divides or reproduces. This is called DNA replication.

where does DNA replication take place?

• DNA replication takes place in the nucleus of the cell.

The first step of DNA replication

• An enzyme called Helicase unwinds and breaks the hydrogen bonds between the base pairs (separating the two strands)

what does polymerase do? (second step)

An enzyme called DNA polymerase reads and adds in the complimentary nitrogenous base to each existing strand.

a complimetary strand is…

• reated for each of the two original DNA strands.

Result of DNA replication

•  Two new identical DNA strands are produced, each containing the original strand and the new strand.

What does DNA stand for

deoxyribonucleic acid

where does DNA reside

the nucleus

double helix

The shape is described as a twisted ladder or

sides of the ‘ladder’ “double helix”

• Deoxyribose (five-sided sugar)

Phosphates

rungs of the ladder are?

nitrogen bases

four types of nitrogen bases

• Adenine only pairs with Thymine

Cytosine only pairs with Guanine

DNA is?

Double stranded and has the base of thymine

What does RNA have instead of thymine

Uracil

what is the sugar in DNA

deoxiribose

what is the sugar in RNA

Ribose

what bases do both DNA & RNA have?

adenine, guanine, & cystosine

What nitrogeneous base does RNA not have

Thymine

What is the main difference between DNA & RNA

The main difference between DNA and RNA is that RNA uses uracil where DNA uses thymine. 

DNA is a nucleic acid polymer composed of which repeating structural unit?

nucleotides

what is the role of RNA

to move information from the nucleus to the ribosomes for protein synthesis

which structural charecteristic is seen in RNA and not in DNA

a single strand

Which base is found only in RNA?

uracil

A single strand of DNA helix has the code CGCTAA. Which would be the complementary code on the other strand of the helix?

GCGATT

Which is the complementary strand of RNA?

UGGCUCGAA

which RNA base pairs with the adenine in DNA

uracil

Which structural component is found in DNA but not in RNA?

deoxiribose

State the names of the nitrogenous bases found in DNA and RNA.

Cytosine (DNA and RNA)
Thymine (DNA only)
Guanine (DNA and RNA)
Adenine (DNA and RNA)
Uracil (RNA only)

what did Chargaff determine

Chargaff determined that there are equal numbers of A and T bases and G and C bases in a DNA sample.

how many hydrogen bonds are there to adenine & thymine

2 hydrogen bonds

how many bonds are between guanine and cytosine

2 hydrogen bonds

Primase

What enzyme puts down the RNA primer so DNA Polymerase can "print" on the 5' side of DNA?

What enzyme is responsible for putting the fragments together?

ligase

The components of DNA are similar for all living organisms?

true

what is the function of DNA

storage of genetic information

where does DNA replicate

Eukaryotic: Nucleus
Prokaryotes: cytoplasm
Wherever DNA is located in an organism

5 enzymes involved in DNA replication

• Helicase: Unwinds the DNA double helix by breaking hydrogen bonds between the strands 

• Primase: Synthesizes RNA primers that DNA polymerase uses to start copying DNA 

• DNA polymerase III: The main enzyme that extends the DNA strand in prokaryotes 

• DNA polymerase I: Replaces RNA primers with DNA 

• Ligase: Fills in gaps in the DNA strand by forming bonds between nucleotides 

D NA written out

ATTCCGATA

TAAGGCTAT