bio 3

RNA processing / editing make

All three types of RNA made by transcription

Reused

rRNA+ tRNA get Used over and over again, not made very often

Recycled

mRNA Made each time a cell needs to make a protein, made often( once the cell is done using it the nucleotides are recycled)

Does DNA have non coding regions

DNA has non-coding regions that interrupt coding regions( instructions for making proteins)

Does RNA have non coding regions

mRNA also contains non-coding regions, but they get edited out before mRNA leaves the nucleus (right after transcription)

introns

pieces of mRNA that are edited out (non-coding)

exons

pieces of mRNA that are kept(coding)

RNA processing / editing

Introns are cut out of mRNA + exons are put together to make final mRNA

polypeptide

chain of amino acids

protein

one or more polypeptides with a certain structure( shape) and function(job)

two steps

transcription+ editing of mRNA, translation.

What is translation?

putting together amino acids to make a polypeptide that will become a protein

Why does translation happen?

to make proteins

When does translation happen?

during G1 and G2 of interphase

Where does translation happen?

on ribosomes in the cytoplasm

how does translation happen?

rRNA, mrna, TRNA work together to do translation

what is the end result of translation?

a polypeptide

Codon

three nucleotides on mRNA

anticodon

Three nucleotides in tRNA

anticodon is complementary to codon
allowed TRNA to bring correct amino acids in correct order

genetic code

- allows us to translate between nucleotide in mRNA +amino acids in polypeptide
- more codon than amino acids overlap in the code
- start codon+ three stop codons

mutation

permanent change in nucleotide sequence of cells DNA
- some mutations are passed down+ some are not
- can be harmful or have no effect
can be random accidents or caused by mutagen

what is mutagen

- outside factor that causes mutation example chemical radiation

what type of mutation are we focusing on

point mutation, a change in base pair

Two types of point mutation

substitutions and frameshift mutations

substitution

base pair is different, May or may not result in different amino acids( because of overlap and genetic code)

frameshift mutation

insertation( extra pair) or deletion( missing base pair), shifts whole reading frame, changes all amino acids from that point on

DNA structure

-2 strands of nucleotides (double helix, 2 strands are twisted) -deoxyribose & phosphate alternate on outer edges (back bone of DNA)
-Base pairs in the middle are held together by hydrogen bonds

Base pairing rule for A T

A\=T (2 hydrogen bonds)

Base pairing rule for C G

C≡G (3 hydrogen bonds)

Are strands of DNA parallel or anti parallel

anti-parallel

What does anti parallel mean?

lines sided by side, but facing opposite directions

What is the DNA replication process?

Copying DNA

why does the DNA replication process happen?

getting cell ready to divide so daughters cells have correct DNA

When does the DNA replication process happen?

During the Synthesis of interphase

Where does the DNA replication process happen?

In the nucleus of eukaryotic cells

How does the DNA replication process happen?

1. DNA uncoils/unravles
2. strands seperate (DNA unzips0
3. New complementary DNA nucleotides are added to both strands
4. RESULT: 2 identical DNA Molecules (each is 1/2 old and 1/2 new)

complementary nucleotides

match up according to base pairing rules

Original (old) strands are used as a template for....

New strands (to know which nucleotide to add)

What is the process of DNA replication

semi-conservative, each DNA molecule at the end of the process is 1/2 old and 1/2 new

\# of strands in RNA

one

\# of strands in DNA

two

Sugar in RNA

ribose

Sugar in DNA

deoxyribose

Instead of thymine, RNA has...

Uracil (U)

Full name of RNA

ribonucleic acid

Overall role of RNA

involved in process that makes proteins from instructions in DNA

Role of mRNA (messenger RNA)

brings instruction for making proteins from DNA nucleus to ribosomes in the cytoplasm

rRNA (ribosomal RNA)

type of RNA that makes up the major part of ribosomes (ribosomes \= rRNA +Proteins)

tRNA (transfer RNA)

carries amino acids to the ribosomes according to the info in mRNA. (amino acids put together make proteins)

Transcription

process that makes all RNA types

What is transcription?

Making any type of RNA using info in DNA

Why does transcription occur?

To make proteins without DNA leaving nucleus

When does transcription occur?

during G1 and G2 of interphase

Where does transcription occur?

inside the nucleus of a eucaroytic cell

How transcription works

1. DNA uncoils
2. DNA unzips (strands separate)
3. New complementary RNA nucleotides added to only PART of ONE strand of DNA, using DNA as a template to make RNA.
4. Result: Original DNA molecule + 1 RNA molecule (one piece of RNA)

Enzymes included in transcription....

gyrase, helicase, RNA polymerase

What does RNA polymerase do?

helps add RNA nucleotides

DNA replication: Where in eucaryotic cells does the process happen?

Nucleus

Transcription: Where in eucaryotic cells does the process happen?

Nucleus

DNA replication: Does at least part of the DNA need to be coiled and unzipped at the beginning of the process?

yes

Transcription: Does at least part of the DNA need to be coiled and unzipped at the beginning of the process?

yes

DNA replication: How many of the DNA strands are used as a template in the process?

2

Transcription: How many of the DNA strands are used as a template in the process?

1

DNA replication: Is all of the DNA in the cell being copied during the process?

yes

Transcription: Is all of the DNA in the cell being copied during the process?

no

DNA replication: Is part of the DNA being rewritten into a different form during the process.

no

Transcription: Is part of the DNA being rewritten into a different form during the process.

yes

DNA replication: Which type of nucleotides are added in the process?

DNA

Transcription: Which type of nucleotides are added in the process?

RNA

DNA replication: Of the enzymes we discussed, which ones are involved in the process?

Gyrase, Helicase, DNA polymerase, ligase

Transcription: Of the enzymes we discussed, which ones are involved in the process?

Gyrase, helicase, RNA polymerase

DNA replication: Does the process involve the lagging strand and Okazaki fragments?

Yes

Transcription: Does the process involve the lagging strand and Okazaki fragments?

No

DNA replication: What is the end product that is created during the process?

DNA

Transcription: What is the end product that is created during the process?

RNA

DNA replication: Why does the process need to happen? (What is the cell getting ready to do?)

Prepare for cell division

Transcription: Why does the process need to happen? (What is the cell getting ready to do?)

to make proteins

Bad things that would happen if cells were too big

-Larger cells are less efficient at moving nutrients + wastes
throughout the cell and in/out of the cell

Information overload

-not enough DNA to deal with needs of the whole cell
-cell puts to many demands on DNA

Cell Division - purpose (what it's used for)

replacing, old or damaged cells
•growing
• reproduring (making offspring)

asexual reproduction

-1 parent
-genetically identical offspring
-only involves cell division(fast &simple)
-most common in unicellular orgs.

sexual reproduction

-2 parents
-offspring are combination of parents
-involves cell division+more (takes longer , more complex)
-more common in multicellular orgs.

Chromatin

-the substance in the nucleus of eukarotic cells
- made of DNA + proteins
-proteins called histones help DNA coil in organized way to fit inside nucleus

What happens when chromatin is tightly coiled

chromosomes form

what are the steps of interphase?

G1, S, G2

What happens in the G1 phase of interphase?

cell grows, makes more organelles, performs its normal function

What does S stand for?

synthesis

What happens in the S phase?

DNA replicated (copied)

What happens in the G2 phase?

Similar to G1+ cell getting ready to divide

What happens in M phase

division

nucleus dividing is called.....

mitosis or meiosis

cell dividing is called....

cytokinesis

Important Early discoveries

That DNA is the genetic material (not proteins)

bacterial transformation (transformation) (another important discovery)

one strain of bacteria can take on characteristics of another strain by taking in pleces of DNA

bacteriophage (other important discovery)

A virus that infects bacteria

Roles of DNA

-storing information, copying information, and transmitting information
-genetic info is expressed and used as instructions for making proteins
-proteins give cells their genetic traits

Where was erwin chargaff born

austria-hungary

When was erwin chargaff born

1905

When was erwin chargaff died

2002