Unit 1: Protein & Nucleotides

Question 1

DNA

Answer 1

Deoxyribonucleic Acid (G, C, A, T)
- Double-stranded

Question 2

RNA

Answer 2

Ribonucleic Acid (G, C, A, U)
- ribose (sugar) has a hydroxyl group (OH) on the 2’ carbon atom
- additional O makes RNA more unstable
- mRNA (messanger), tRNA (transfer), rRNA (ribosomal)
- single-stranded; flexible

Question 3

Pyrimidines

Answer 3

Smaller nitrogenous base (cytosine, uracil, and thymine)

Question 4

Purines

Answer 4

Larger nitrogenous base (adenine and guanine)

Question 5

Name the 5 bases and their location

Answer 5

thymine (DNA), uracil (RNA) and cytosine, guanine, adenine (both)

Question 6

Which nitrogenous bases bond together?

Answer 6

In DNA: guanine -> cytosine, adenine -> thymine
In RNA: guanine -> cytosine; adenine -> uracil

Question 7

Which directions do nucleotides bond?

Answer 7

to the 5’ and the 3’

Question 8

name protein functions

Answer 8

transportation, storage, gene expression, enzymes that catalyze chemical reactions in cells, structure, regulation, movement, signaling, and protection/defense

Question 9

name RNA functions

Answer 9

enzymes to catalyze reactions, stores and transfers information, replicates DNA molecules, synthesizes proteins for cells, and regulates gene expression

Question 10

name DNA functions

Answer 10

stores information

Question 11

protein

Answer 11

molecules formed from subunits called amino acids; one or more polypeptides that have a biological function

Question 12

amino acids

Answer 12

carbon bonded to an amino group (NH^2), a carboxyl group (COOH), a hydrogen atom, and a R-group
-each type has a different R-group and they can control the functions
- 20 standard amino acids
- short chain is peptide; longer chain is polypeptide
- has primary, secondary, tertiary, and quaternary structure
- monomer of protein

Question 13

primary structure

Answer 13

a unique sequence of amino acids in a polypeptide
- determines the overall shape and function in a protein

Question 14

secondary structure

Answer 14

describes how sections of a polypeptide sometimes fold along its length, and the most common of these structures are α-helixes and β-pleated sheets

Question 15

tertiary structure

Answer 15

a single polypeptide chain “backbone” with one or more protein secondary structures

Question 16

quaternary structure

Answer 16

proteins which are themselves composed of two or more polypeptides and are folded in a multi-subunit complex.

Question 17

Genome

Answer 17

all genetic information of an organsim

Question 18

3 conversions in cells

Answer 18

1. DNA -> RNA (transcription)
2. RNA -> Proteins (translation)
3. RNA -> DNA (reverse transcription)

Question 19

eukaryotes

Answer 19

cells with nuclei
- protein flow of info: DNA -> pre-mRNA -> mature mRNA -> proteins
- processes mRNA

Question 20

gene

Answer 20

a section of DNA that codes for one or more related proteins or functional RNA

Question 21

promoter

Answer 21

a sequence of DNA nucleotides that is an attachment point for the enzyme RNA polymerase, which synthesizes RNA
- before trancription starts

Question 22

transcription

Answer 22

DNA strands briefly separate, and only the template strand is used. RNA is synthesized in the 5’ -> 3’ direction, so the template strand is read 3’ -> 5’. Terminator is a sequence of DNA nucleotides near the end of a gene that is transcribed and also contains the signal to stop transcription. pre-mRNA, an eukrayote, is the result.

Question 23

mRNA processing

Answer 23

Regions of eukaryotic genes that code for a product (exons) are interrupted by regions that will not code for the product (introns). This elimination of introns while fusing the exons is called splicing. Enzymes add a 5’ cap (guanine nucleotide with three phosphates) to the 5’ end while they add a poly(A)tail of adenine nucleotides to 3’ end.

Question 24

genetic code

Answer 24

specifies how nucleotide sets encode the amino acids found in proteins
- amino acids are determined by three sets of three DNA or RNA nucleotides called codons
- AUG : start codon, methionine
- UAA, UAG, UGA : stop codons
- unambiguous, nonoverlapping, redundant, and nearly universal in organisms

Question 25

translation

Answer 25

tRNA have an amino acid attachment site on one end of the molecule and an anticodon located on the other end. Each tRNA carries its amino acid and binds to a matching mRNA codon for translation
- mRNA, transfer RNA (tRNA), and a complex of proteins and ribosomal RNA (rRNA) called a ribosome
- read 5’ -> 3’

Question 26

ribosome

Answer 26

link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains
- E site is on the left, P site is in the middle, A site is on the right
- perform mRNA translation
- made up of two units

Question 27

P site

Answer 27

where the tRNA that is still attached to the growing protein is located
- in the middle

Question 28

A site

Answer 28

where a new tRNA carrying an amino acid (“charged” tRNA) enters the ribosome and binds to a codon
- on the right side

Question 29

E site

Answer 29

where the tRNA that has released its amino acid (“uncharged” tRNA) exits the ribosome
- on the left side