Bio Unit 8

in the center (nucleus) of every cell

Where is DNA found?

Dexoyribonucleic acid

What does DNA stand for?

nucleic acid

what type of organic molecule is DNA?

- very long strand of genes

- genetic information to pass on to the next generations

- information to direct the activities of the cell

- instructions to make proteins

What does DNA contain?

polymer

long molecule of repeating units called monomers

nucleotide

what is one monomer called in DNA

- deoxyribose: sugar with 5 carbon

- phosphate group: PO4 (smallest part)

- base: nitrogen containing molecules

what are the parts of the nucleotide of DNA?

- Adenine (A)

- Thymine (T)

- Cytosine (C)

- Guanine (G)

What are the 4 bases of DNA?

- bases in the middle

- sugar and phosphate on the sides

what do the nucleotides connect with?

- sugar and phosphate make the backbone on ladder

- bases make the rungs

what makes up "ladder" of the 2d shape of DNA?

double helix

What is the 3D shape of DNA called?

TRUE

T/F: the bonds between the bases are hydrophobic

TRUE

T/F: the bonds between the bases are weak

base pairing rule

the bases pair up with the same bases every time

Thymine

What base goes with Adenine?

Cytosine

What base goes with Guanine?

the double helix structure

Watson and Crick used the base pairing rules to discover what about DNA?

2 bonds

How many bonds are needed for Adenine and Thymine?

3 bonds

How many bonds are needed for Guanine and Cytosine?

sugar, phosphate

the side of the DNA ladder are made up of alternating ________ and ______________ groups.

bases

The rungs of the DNA ladder are made up of ____________

Hydrogen

paired bases are held together by weak bonds called _____ bonds

helix

when the DNA ladder twists the way it normally does, the shape of the molecule is call a ______

phosphodiester bond

what are the bonds that are formed between the sugar phosphate called?

deoxyribose

name of the sugar found in DNA

original strand of DNA divides and makes 2 complete strands

- always half original and half new

What is the basic principle of DNA replication?

Meselson-Stahal

who proved how DNA replication occurs?

original strand of DNA divides and makes 2 complete strands

what did meselson-stahl's experiment prove?

-use 2 different isotopes of nitrogen to build the DNA

- original DNA uses N15 isotope (heavier)

- new DNA use N14 isotope (lighter)

-centrifuge after 1 and 2 replications

-form a "line" based on weight

- heavy N15 line

- light N14 line

- if mixed original and new, line would be between N14 and N15

what was meselson-stahl's method?

- 2 original strands stay together- original is "conserved"

-2 new strands are formed

describe the conservative stage in meselson-stahl's experiment

after 1st replication

- each DNA is half new, half original

after 2nd replication

- some are all new- some are 1/2 and 1/2

describe the semi-conservation stage in meselson-stahl's experiment

after 1st replication

- each DNA is half original

- in "chunks"

after 2nd replication

- all are part old part new- in "chuncks"

describe the dispersive stage in meselson-stahl's experiment

-compare to the predictions

- 2 possibilities after 1 round

- only 1 possible after 2 rounds

-conclusion

- semi-conservative is correct method

what was meselson-stahl's experiment conclusion?

- before cell division

- during S phase of interphase

When does DNA replication occur?

each new cell produced will have a full set of DNA

what is the purpose of DNA replication?

origins of replication

- spot on DNA where replication begins

- multiple origins

Where does DNA replication occur?

helicase

enzyme that break the hydrogen bond between bases

single strand binding proteins

hold the 2 stands of DNA apart

topoisomerase

enzyme that reduces tension on DNA strands as it unwinds

-relaxes the supercoil

-prevents tangling

primer

short section of RNA that is built at the beginning of DNA replication

primase

enzyme that builds RNA primer

leading strand

new strand built off "top" strand with 3' at the end

-continuous strand

-only one RNA primer required

lagging strand

new strand built off "bottom" strand with 5' at end

okazaki fragments

short, backwards section on the lagging strand

ligase

glues okazaki fragments together

nuclease

enzyme that cuts out the incorrect DNA nucleotide

DNA polymerase III

enzyme that adds the new DNA nucleotides

DNA polymerase I

replaces RNA bases

- original DNA strand unwinds and unzips

- priming DNA synthesis

- elongating New DNA strand

- antiparallel elongation

- leading strand

- lagging strand

What are the steps of DNA Replication?

- Helicase enzyme breaks the hydrogen bond between the bases

- single strand binding proteins hold the 2 strands apart

- topoisomerase enzyme reduce tension on DNA strand as it unwinds to prevent it from tangling

describe original DNA strand unwinds and unzips during DNA replication

- DNA cannot build from "nothing"

- needs primer to connect to

- 5-15 nucleotides long

describe priming DNA synthesis in DNA replication

- new DNA nucleotides are added

- DNA Polymerase III adds the new DNA nucleotides

- 1st to the RNA primer then to DNA nucleotides

describe elongating new DNA strand in DNA replication

- 2 strands run antiparallel

-one has 5' end: phosphate on top

-3' end: phosphate on bottom

-other has 3' on top and 5' on bottom

- DNA polymerase III can only add to 3' end

- creates challenge to build the new strands

- build "top" and "bottom" strands using different method

describe antiparallel elongation in DNA replication

- new strand built off "top" strand with 3' at end

- continuous strand

- only one RNA primer required

describe the leading strand in DNA replication

- new strand built off "bottom" strand with 5' end

- can't add to 5' bottom

- built in short backward sections

describe the lagging strand in DNA replication

- joined by ligase

- but first RNA primer section needs to be replaced with DNA base pairs

- DNA polymerase I replaces RNA bases

in DNA replication how are the Okazaki fragments connected

- Nuclease cuts out the incorrect DNA nucleotide

- DNA polymerase fills in missing nucleotides

- ligase connects them

what does nucleotide excision repair do?

- UV radiation

- food colorings

- tobacco products

- chemical radiation

What are examples of things that could cause DNA mutations?

anti-parallel structure

go in opposite directions, but bridge with these nitrogenous bases

- discovered the process of bacterial transformation

- goal: develop a vaccine for pneumonia

What did Griffith credited with discovering and what was the goal of his experiment?

confirmed DNA as the molecule of heredity

What did Avery, McCarthy, and Macleod do?

1. some organism can acquire new properties from their environment and from one another

2. non-heritable exchange of genetic information is possible

What are 2 conclusions of Griffith, Avery, McCarthy, and Macleod?

What is the genetic material of the phage, DNA, and protein?

- experiment: set 1 being bacteriophage coat protein labeled with S^35 and set 2 being bacteriophage DNA labeled with P^32

What was Macleod and McCarthy trying to answer and how did they set up their experiment?

DNA is the genetic material

What was the conclusion of Macleod and McCarthy's experiment?

came up with a structured way of thinking about these inheritance

What did Mendel come up with/discover?

came up with the chromosome theory

What did Sulton and Boveri come up with/discover?

chromosomes are the basis for where these heritable factors are

What did Morgan come up with/discover?

- the frequencies of the nitrogenous bases in DNA varies across species

- the frequency of guanine is equal to the frequency of cytosine in DNA

What 2 conclusions did Chargaff have?

experiment: imaging diffraction patterns from x-rays beamed into crystals of DNA

contribution: confirmed it was a helical structure

What did Franklin experiment with and what was the key contribution of her work?

they established that DNA was a double helix, had the base pairs forming rungs of he double helix --> showed how DNA could replicate itself, it could contain actual information

What did Watson and Crick do?

helped Watson and Crick get Franklin's work

What did Wilkins do?

- worked on the structure of viruses

- her work revolutionized medicine, biology, and agriculture

What were Franklin's contributions to science?

origin of replication

location on DNA where replication begins, forms the replication bubble

centrifuge

tool used to separate the various isotopes used in the DNA Replication experiments

template

original DNA strand

- DNA carries instruction for making proteins

- DNA is found in the nucleus

- proteins are made in the cytoplasm

- DNA can't leave nucleus

- RNA copies instructions from DNA (in the nucleus) and carries inforto the ribosomes in the cytoplasm

Why do we need RNA?

RNA

ribonucleic acid

polymer = long chain of nucleotides

what is the structure of RNA?

ribose

what types of sugar is RNA made of?

Uracil

In RNA, what base pairs with Adenine?

TRUE

T/F: RNA is only single stranded

nucleus and cytoplasm

Where is RNA found?

FALSE: RNA is temporary

T/F: RNA is always there

mRNA, tRNA, rRNA

What are the three types of RNA?

- messenger RNA

- made in nucleus

- moves to cytoplasm

- carries instruction for one protein

- one long strand of bases

What is mRNA and what does it do?

- transfer RNA

- found in cytoplasm

- carries amino acid to mRNA for assembly in order

- folded into a "t" shape with bases at one end and amino acid at the other

What is tRNA and what does it do?

- ribosomal RNA

- found in cytoplasm

- ribosomes are made of rRNA and proteins

- small subunit and large subunit

- connects the amino acids from tRNA to make new protein

- remember ribosome = makes proteins

What is rRNA and what does it do?

transcription

process to make mRNA from DNA

in the nucleus

where does transcription occur?

promoters

"on" switches at the beginning of a gene

- mark beginning of instructions for a single protein

mRNA to start building

promoters tells where __________

gene

section of DNA that carries instructions for a single protein

1. RNA polymerase finds the promoter region

2. RNA polymerase unwinds DNA(Initiation)

3. RNA polymerase adds new RNA nucleotides (Elongation)

4. RNA polymerase reaches the "stop" sequence (Termination)

5. mRNA strand leaves nucleus

6. DNA rezips

What are the steps of Transcription?

Initiation

RNA polymerase unwinds DNA

elongation

RNA polymerase adds new RNA nucleotides

termination

RNA polymerase reaches the "stop" sequence

- RNA is made of ribose

- only one strand

- Adenine pairs with Uracil

- found in nucleus and cytoplasm

- RNA is temporary

- There are three types of RNA

How is DNA different from RNA?

studied mRNA and turning it into a whole new field of medicine

What did Katalin Kariko study?

they use genetic information of the virus, where traditional vaccines use dead or weakened viruses

How are mRNA vaccines different from traditional vaccines?

it is very fragile and enzymes in the human body can break it down

What is the disadvantage of RNA?