Theme 1B

Question 1

What molecules are found in nucleic acids?

Answer 1

Pentose sugar: ribose (RNA) or deoxyribose (DNA)

Nitrogenous base: purines or pyrimidine

Phosphate group

Question 2

The pentose sugar of RNA has a _______ group on its carbon 2

Answer 2

OH

Question 3

The pentose sugar of DNA (deoxyribose) has a _____ on its carbon 2

Answer 3

H atom
Not OH

Question 4

What are the nitrogenous bases used in DNA? In RNA?

Answer 4

DNA : ACGT
RNA: ACGU

Question 5

Look at each nitrogenous base and identify which is which

Answer 5

LOOK ON GOOGLE DOC

Question 6

What is a nucleoside.

Answer 6

Molecule of a sugar and a nitrogenous base

Question 7

What carbon does the base bind to in a nucleoside.

Answer 7

Carbon 1

Question 8

What is a nucleotide.

Answer 8

And nucleoside molecule but also with a phosphate group attached to carbon 5 of the sugar

Question 9

What parts are DNA composed of

Answer 9

A bunch of deoxyribonucleotides.

Question 10

Which carbons on the sugars in DNA are attached to the phosphate

Answer 10

C5 and C3

Question 11

What causes DNA (polynucleotide) to be polar.

Answer 11

The 5 carbon end with phosphate group

The three carbon end with OH group

Question 12

What charge is a dna molecule, why?

Answer 12

Negative because of the negatively charged phosphates in the pentose phosphate backbone

Question 13

Ended on Slide 8

Question 14

What is x ray diffraction

Answer 14

They have x ray source and it shoots beam of x rays to the DNA sample. The beam diffracts (splits) then shows pic of dna on photographic plate

Question 15

What did x ray diffraction show us of dna

Answer 15

Showed that DNA was cylindrical and around
2mm in diameter
Showed 0.34nm periodicy (that base were stacked on top of one another)
Show x shaped pattern which indicated helical structure

Question 16

What is a purine on one strand of dna always paired with?

Answer 16

A pyrimidine on the others strand (this fits chargaffs rule

Question 17

The backbone of DNA is ___
, and the bases
(interior) are ___

Answer 17

Polar hydrophilic
Nonpolar hydrophobic

Question 18

Why are the two strands of dna antiparallel?

Answer 18

Allows bases to properly line up with each other

Question 19

What keeps the two strands of dna intact/ connected

Answer 19

Hydrogen bonds between the bases

Question 20

What is a major groove, what is a minor groove

Answer 20

Major groove: when the backbone of the helix is further apart
Minor: the backbone of the helix is closer together

Question 21

What is nucleic acid hybridization?

Answer 21

Putting together (annealing) single strands of RNA and DNA.
This process is temperature driven and concentration dependant

Question 22

How do you put together (annealing) single strands of RNA to DNA.

Answer 22

First denature the original strand through heat, this splits the stand into two
Then add the RNA strand to the strand that compliments it
Then reanneal DNA strand to RNA strand through cooling

Question 23

What is semiconservative replication?

Answer 23

Where the double helix has the original parent strand, and the newly made (daughter) strand

Question 24

What structure is DNA organized into? What makes up half of this structure?

Answer 24

Chromosomes
Proteins

Question 25

What is chromatin

Answer 25

Region of dna with its associated proteins on a chromosome

Question 26

What shape can chromosomes be? How can you tell the shape?

Answer 26

Circular or linear If you cut the chromosome and there's only piece, it's circular If two piece, linear

Question 27

How many and what shape are prokaryotes chromosomes? What are their chromosomes called and where are they?

Answer 27

One circular chromosome Called plasmids are in the cytoplasm

Question 28

What shape are eukaryotic chromosomes, where are they?

Answer 28

Linear in the nucleus

Question 29

Plasmids _________ required for life

Answer 29

Are not

Question 30

What are the components of eukaryotic chromosomes?

Answer 30

Origins of replication Centromeres Telomeres

Question 31

What is the origin of replication?

Answer 31

DNA sequences along chromosome that initiate DNA replication (where dna replication starts)

Question 32

What is a centromere?

Answer 32

The DNA sequences that correctly segregate the chromosomes by directing where the kinetocore forms. Helps the spindles attache to the correct kineticore

Question 33

What are telomeres

Answer 33

DNA sequences at the end of chromosomes that prevent degradation and help with having proper replication of the chromosomal ends

Question 34

What are diploid sets, haploid sets of chromosome?

Answer 34

Diploid is two copies of chromosome Haploid is one copy of chromosome

Question 35

What organisms have a haploid set of chromosome? Why

Answer 35

Sexually reproductive cells (sperm or eggs). Because they are less complex

Question 36

What organisms have a diploid set of chromosome? Why

Answer 36

Eukaryotic cells, more complex

Question 37

Why is DNA compacted into chromosomes?

Answer 37

So that the entire thing can fit into the cell/nucleus The chromosome structure protects the DNA from damage since exposed DNA is unstable Chromosomes are easily separated and sent to each daughter cell during cell division

Question 38

What are histones? Why is that their charge?

Answer 38

Basic positively charged proteins that DNA winds around Charged positive because DNA is negative

Question 39

What are nucelosome

Answer 39

Histone octamers (8 histones tied together)

Question 40

What does histone 1 do?

Answer 40

Binds nucleosomes and linker DNA to form 30nm chromatin fibre

Question 41

Do prokaryotes have histones?

Answer 41

No, but they do have some positively charge proteins associated with DNA

Question 42

Why do bacterial chromosomes not need to be as compact as eukaryote chromosome?

Answer 42

genome size in eukaryotes is higher, so it needs more compact chromosome genome in prokaryotes is less so it doesn't need to compact chromosomes as much.

Question 43

What is euchromatin, why is it a thing?

Answer 43

It is regions of lower dna compaction where the genes are actively expressed It's a thing because dna packing across the chromosome is not uniform

Question 44

What is heterochromatin, why is it a thing

Answer 44

is regions of higher dna compaction where the genes expression are silenced It' silenced because the dna needs to be unzipped to be transcribed. If it's too compact, proteins can't get in and expresses gene

Question 45

What is constitutive heterochromatin?

Answer 45

Regions Wherethe dna is always highly compacted (Centromeres and subtelomric regions)

Question 46

What is facultative heterochromatin?

Answer 46

When the regions can switch to euchromatin depending on cell type and during development