(SBI4U1) Protein Synthesis

Question 1

What builds the proteins?

Answer 1

Ribosomes

Question 2

What needs to get out of the nucleus to the ribosome in order to be used to build proteins?

Answer 2

DNA

Question 3

How does the DNA code get out of nucleus?

Answer 3

Crick’s central dogma
DNA + Transcription = RNA
RNA + Translation = Protein

Question 4

Proteins are ________ made of several ________ called _____ _____

Answer 4

Polymers
Monomers
Amino acids

Question 5

Proteins are built from combinations of the __ different amino acids

Answer 5

20

Question 6

In order to obtain at least 20 different amino acids, _ bases are needed to code for _ amino acid

Answer 6

3

1

Question 7

What are the three bases needed to code for 1 amino acid called?

Answer 7

Codon

Question 8

True or false:

The genetic code is redundant

Answer 8

True, one amino acid can be produced by more than one codon

Question 9

RNA is found in both the _______ and _________

Answer 9

Nucleus

Cytoplasm

Question 10

DNA is found only in the _______

Answer 10

Nucleus

Question 11

If the DNA can’t get to the ribosomes to do protein synthesis by itself, what must happen?

Answer 11

Information stored in DNA must be carried to the ribosome using RNA

Question 12

What is the purpose of transcription?

Answer 12

To accurately copy the information in DNA into an RNA molecule

Question 13

How does the cell know where to start transcription?

Answer 13

Cells need to find the specific sequences (genes) that need to be transcribed

Question 14

The sequences that are recognized as the _________ _____ for transcription are called what?

Answer 14

Starting point

Are called: promoter sequences

Question 15

What is a promoter sequence?

Describe it

Answer 15

TATA box

Contains repeating T and A nucleotides, acts as the starting point for transcription

Question 16

___ ___________ binds to the promoter/TATA box sequence to start building the RNA strand

Answer 16

RNA polymerase

Question 17

True or false:

In the initiation of transcription, the RNA strand built is not complementary to the DNA

Answer 17

False, the RNA strand is complementary to the DNA

Question 18

DNA is organized into segments called what?

Answer 18

Genes

Question 19

Each gene codes for what?

Answer 19

A different protein product

Question 20

The code that builds protein (______) is found _____ the ____ sequence (_____ ___)

Answer 20

Codon
After
TATA
TATA box

Question 21

RNA polymerase works in what direction to build RNA?

Answer 21

5’ to 3’

Question 22

True or false:

RNA has okazaki fragments

Answer 22

False, RNA is single stranded, so there’re no Okazaki fragments

Question 23

Transcription involves __ proof reading, so ________ are made

Answer 23

No

Mistakes

Question 24

What does transcription produce?

Answer 24

mRNA (Messenger RNA)

Question 25

The mRNA is _____________ to the DNA it was made from

Answer 25

Complementary

Question 26

What stops transcription on the DNA strand?

Answer 26

Terminator sequences (G's, C's, & A's)

Question 27

What detaches from DNA once strand is at terminator sequence? (2)

Answer 27

``` RNA polymerase Messenger RNA (mRNA) ```

Question 28

What is the mRNA strand produced during transcription called?

Answer 28

Pre-mRNA

Question 29

True or false: | The pre-mRNA is processed in 2 steps

Answer 29

False, the pre-mRNA is processed in 3 steps

Question 30

What are the 3 steps of processing pre-mRNA?

Answer 30

1. Add a 5' cap 2. Add a Poly-A tail 3. mRNA splicing

Question 31

What is a 5' cap?

Answer 31

Modified G nucleotide added to 5' end

Question 32

What is a Poly-A tail?

Answer 32

A nucleotides that are added to 3' end

Question 33

Genetic codes contain coding sequences and noncoding sequences, what are they called?

Answer 33

Exons (coding sequences) | Introns (noncoding sequences)

Question 34

What removes introns and reconnect exons in the mRNA transcript?

Answer 34

Spliceosomes

Question 35

Spliceosomes remove _______ and reconnect _____

Answer 35

Introns | Exons

Question 36

What is needed in translation?

Answer 36

``` Transfer RNA (tRNA) Ribosomes ```

Question 37

What is the function of the tRNA?

Answer 37

Reads the message on the mRNA and carries amino acids to the ribosome to build a polypeptide

Question 38

How does the tRNA recognize the mRNA codon?

Answer 38

Using an anticodon

Question 39

What is an anticodon?

Answer 39

3 nucleotides that are complementary to the mRNA codon

Question 40

The 3' end of the tRNA is where what attaches?

Answer 40

Amino acid

Question 41

Ribosomes have _ binding sites for tRNA molecules

Answer 41

3

Question 42

What are the 3 binding sites of the ribosome?

Answer 42

P site A site E site

Question 43

What is the function of the P site in the ribosome?

Answer 43

Holds one tRNA and the growing chain of amino acids

Question 44

What is the function of the A site in the ribosome?

Answer 44

Holds tRNA bringing the next amino acid

Question 45

What is the function of the E site in the ribosome?

Answer 45

Releases tRNA molecules as the ribosome shifts over to read the next codon

Question 46

What is the first part of translation?

Answer 46

Initiation

Question 47

What happens in initiation in translation?

Answer 47

mRNA reaches the cytoplasm mRNA sticks to the rRNA in the ribosome tRNA with the anticodon complementary to the first codon binds to the mRNA in the P-site

Question 48

What RNA is in the ribosome?

Answer 48

rRNA

Question 49

Initiation in Translation: | ____ with the anticodon complementary to the first codon binds to the _____ in the _-site

Answer 49

tRNA mRNA P

Question 50

What is the second part of translation?

Answer 50

Elongation

Question 51

Elongation in Translation: | The next ____ molecule binds to the ____ codon in the _ site

Answer 51

tRNA mRNA A

Question 52

Elongation in Translation: | The existing amino acid chain the _ site is transferred to the amino acid in the _ site by forming a ________ bond

Answer 52

P A Peptide

Question 53

Elongation in Translation: Ribosome moves _ nucleotides over to read the next _____ The tRNA that was in the A site, is now in the _ site The newly exposed codon makes up a new empty _ site tRNA from the P site is now in the _ site

Answer 53

``` 3 Codon P A E ```

Question 54

True or false: | The process of elongation in translation repeats until a stop codon on the mRNA strand is reached

Answer 54

True

Question 55

____ _____ prevents more amino acids from being added to the polypeptide chain

Answer 55

Stop codon

Question 56

_______ ______ frees the polypeptide chain

Answer 56

Release factor

Question 57

When the polypeptide becomes free from the ribosome, what happens?

Answer 57

It will take its shape by folding