Chapter 4 Lecture 1 - DNA Structure and function, organisation into chromosomes, RNA structure and function

Question 1

What do chromosomes contain

Answer 1

DNA and protein

Question 2

What are the monomers of DNA and RNA

Answer 2

Nucleotides

Question 3

What are the three components of nucleotides

Answer 3

Pentose sugar, 1 or more phosphates, nitrogenous base

Question 4

What is the stabilizing component of nucleotides

Answer 4

Pentose sugar

Question 5

What is the difference in molecular structure between RNA and DNA

Answer 5

Ribose has OH on 2’ carbon, while deoxyribose only has a hydrogen on 2’ carbon

Question 6

What is the difference between the two types of nitrogenous bases

Answer 6

One is a single ring, while the other has two rings

Question 7

What are the two types of nitrogenous bases

Answer 7

Pyrimidines and Purines

Question 8

What is the structure of the pyrimidines

Answer 8

Single six membered ring

Question 9

What is the structure of the purines

Answer 9

Six membered ring connected to five membered ring

Question 10

What are the three pyrimidines

Answer 10

Cytosine (C)
Thymine (T)
Uracil (U)

Question 11

What are the two purines

Answer 11

Adenine (A)

Guanine (G)

Question 12

What are nucleotides linked by

Answer 12

Phosphodiester bonds

Question 13

How are phosphodiester bonds formed

Answer 13

Dehydration synthesis of Phosphate of one and sugar of another nucleotide

Question 14

What is the nucleotide chain backbone made of

Answer 14

Sugar-phosphate

Question 15

What is attached to each pentose sugar in nucleotide chains

Answer 15

N base

Question 16

What are the two ends of nucleotide chains called

Answer 16

5’ and 3’

Question 17

What is on the 5’ end of nucleotide chains

Answer 17

Phosphate

Question 18

What is on the 3’ end of nucleotide chains

Answer 18

Sugar

Question 19

What causes nucleotide chains to arrange into the DNA double-helix shape

Answer 19

They are not stable as single chains, so they bond to other chains with matching bases

Question 20

Base Pair

Answer 20

Pair of complementary bases (A-T, A-U, C-G)

Question 21

How are the strands aligned in DNA

Answer 21

Antiparallel, 5’ of one strand, next to 3’ of the other

Question 22

What are bases on opposing chains held by

Answer 22

Hydrogen Bonds

Question 23

What is the law of complementary base pairing

Answer 23

Sequence of 1 strand governs sequence of the other

Question 24

Chromatin

Answer 24

DNA and protein components of chromosomes

Question 25

Chromosome

Answer 25

Threadlike structures in the nucleus that carry genetic information (more compact form of DNA)

Question 26

What does chromatin appear as in the nucleus

Answer 26

Clumps or threads

Question 27

Nucleosome

Answer 27

DNA+histone+linker DNA OR DNA on histones plus “naked” DNA behind it

Question 28

What does DNA do to form chromatin and chromosomes

Answer 28

It wraps around histones

Question 29

Chromosome territory

Answer 29

Each chromosome has its own area within the nucleus

Question 30

When are chromosome territories used

Answer 30

Only in day to day activities, not when dividing

Question 31

How does chromatin condense further

Answer 31

It folds into a zig zag shape, and then continues to condense into irregular loops and coils

Question 32

What happens to chromosomes in preparation for division

Answer 32

They duplicate, and chromosomes consist of two strands of DNA

Question 33

What is one of the two strands making up a duplicated chromosome called

Answer 33

Sister chromatid

Question 34

Centromere

Answer 34

Where the two sister chromatids bind

Question 35

What protein forms on each side of the centromere

Answer 35

Kinetochores

Question 36

What are the 3 main differences between DNA and RNA

Answer 36

• Ribose instead of Deoxyribose
• Has U instead of T (for the pyrimidines)
• Is single stranded instead of double stranded

Question 37

What are the three forms of RNA

Answer 37

• mRNA (messenger)
• rRNA (ribosomal)
• tRNA (transfer)