A1.2 - nucleic acids

Question 1

antiparallel

Answer 1

when 2 strands are parallel but run in opposite direction to each other

Question 2

centrifugation

Answer 2

spinning a sample very quickly to separate the components based on density

Question 3

codon

Answer 3

a group of 3 RNA nucleotide that contain info for the ribosome to insert an amino acid to the polypeptide chain during protein synthesis

Question 4

genetic code

Answer 4

each triplet codon has info used to add an amino acid to the growing polypeptide chain

Question 5

linker DNA

Answer 5

DNA located between nucleosomes

Question 6

octamer

Answer 6

group of 8 histone proteins in the core of each nucleosome

Question 7

pentose

Answer 7

sugar molecules containing 5 carbon atoms

Question 8

nucleotide

Answer 8

a structure composed of a phosphate group, pentose sugar and base joined by covalent bonds

Question 9

what are the characteristics of DNA?

Answer 9

• located in living organisms
• double stranded
• deoxyribose sugar
• adenine, guanine, thymine, cytosine
• helical double helix shape with 2 antiparallel strands

Question 10

what are the characteristics of RNA?

Answer 10

• found in viruses
• single stranded
• ribose sugar
• adenine, guanine, cytosine, uracil
• variety of forms (mRNA, tRNA, rRNA)

Question 11

how are nucleotides joined in DNA and RNA?

Answer 11

covalent sugar-phosphate bond formed by condensation reactions where water is released
- between pentose on one nucleotide and phosphate group of another

Question 12

what are the bases?

Answer 12

• adenine
• cytosine
• guanine
• thymine or uracil

Question 13

DNA

Answer 13

long-term hereditary storage molecules

Question 14

mRNA

Answer 14

messenger RNA leaves the nucleus and brings genetic info to the ribosome during transcription

Question 15

tRNA

Answer 15

transfer RNA brings the correct amino acid to the growing polypeptide chain during translation

Question 16

rRNA

Answer 16

ribosomal RNA carries out translation in the ribosomes

Question 17

ATP

Answer 17

single nucleotide nucleic acid with adenine, ribose and 3 phosphate groups used as a short-term chemical energy store

Question 18

what is complementary base pairing?

Answer 18

• specific bases only pair with each other due to hydrogen bonding
• A and T/U
• G and C

Question 19

how does complementary base pairing allow genetic information to be 1) replicated 2) expressed?

Answer 19

replicated - separating strands of DNA and allowing free DNA nucleotides to base pair with unmatched nucleotides forms an exact cope of the molecule
expressed - separating strands of DNA and allowing free RNA nucleotides to base pair with unmatched nucleotides forms an RNA copy of one strand of DNA which can be used by ribosomes for protein synthesis

Question 20

how is DNA diverse and how does it contribute to its role?

Answer 20

• molecules can have any length and any base sequence
• allows DNA to store huge amounts of data in the genetic code with great economy, contributing to diversity of organisms

Question 21

what evidence is there for a universal common ancestor?

Answer 21

universal genetic code - same codons code for the same amino acids in all organisms
conservation of genetic code - life on earth has evolved from a common ancestor