Before Midterm Lecture 1-18

Question 1

Secondary dna structure

Answer 1

Formed when the backbone of dna interacts non covalently

Question 2

Tertiary structure of dna

Answer 2

Involves the r grips interacting with each other or the backbone structure

Question 3

Quaternary structure of dna

Answer 3

Different polypeptide chains will come together to form a protein

Question 4

Factors affecting membrane fluidity

Answer 4

1. Degree of unsaturation
2. Number of carbons in the chain
3. Sterol content of the membrane

Question 5

In high temperatures and sterol is added to the membrane the fluidity will

Answer 5

Decrease

Question 6

Membrane rafts

Answer 6

Area of reduced fluidity that contains higher concentration of sterols

Question 7

FRAP

Answer 7

fluorescence recovery after photobleaching

Question 8

Integral proteins

Answer 8

Components of the membrane embedded in the phospholipid bilayer that are extractable with strong detergents

Question 9

Peripheral proteins

Answer 9

Transiently attached to inner and outer surfaces that are held by non covalent interactions

Question 10

Peripheral proteins can be displaced from the bilayer via

Answer 10

High salt concentrations

Question 11

Transmembrane panel a proteins

Answer 11

Extend through the entire membrane

Question 12

Lipid anchored panel c proteins

Answer 12

Will be covalently attached to fatty acids or diaglycerides

Question 13

Monolayer panel B associated proteins

Answer 13

Proteins that will be held in place by an alpha helix

Question 14

In electron microscopy the cells have to be

Answer 14

Dead

Question 15

Functions of the membrane

Answer 15

1. Serve as barrier to outside environment
2. Form cellular compartments
3. Control transport process
4. Localize reactions
5. Regulate cell communication

Question 16

Sterols will interact to form

Answer 16

Stacking interactions via their polar alcohol group

Question 17

Fatty acid interactions form

Answer 17

Micelles

Question 18

Triglyceride interactions form

Answer 18

Oil droplets

Question 19

How do phospholipids move across the membrane

Answer 19

Via lateral diffusion

Question 20

Increased fatty acid saturation causes lipids to be

Answer 20

More ordered/ tightly packed

Question 21

How does tail length affect membrane fluidity

Answer 21

Longer tails have a greater surface area, and thus more VWF that hold the tails tightly together making the membrane less fluid

Question 22

Nuclear lamina

Answer 22

Lies directly under inner membrane of nuclear envelope, and is formed by intermediate filaments

Question 23

Steps of active transport into the nucleus

Answer 23

1. NLS signal/ KKKRK
2. NLS protein import complex in cytosol
3. Movement into nucleus through pore
4. Receptor dissociates from nuclear protein
5. NLS remains in nucleus

Question 24

Overall charge on histones

Answer 24

Positive

Question 25

In interphase, dna is known as

Answer 25

Chromatin or the 30 nm fiber

Question 26

Steps of nuclease digestion

Answer 26

Chromatin will be lightly digested with nuclease, associated proteins will be removed, and dna molecules will be separated by size using gel electrophoresis

Question 27

Assumptions of nuclease digestion

Answer 27

1. If there is a repeating protein structure there will be pieces of dna left after digestion 2. Pieces left will have a standard size if they are bound to the same type of structural complex

Question 28

What is SDS-PAGE used to separate

Answer 28

Proteins

Question 29

GEL- Electrophoresis is used to separate

Answer 29

DNA or rna

Question 30

In SDS the gel is made of

Answer 30

Polyacrylamide

Question 31

In electrophoresis the gel is made of

Answer 31

Agarose

Question 32

Is proteins want to undergo gel electrophoresis what must be done first

Answer 32

Pre treatment with SDS and heat to denature and coat proteins will a uniform negative charge

Question 33

Nucleolus is the site of

Answer 33

rRna synthesis and assembly of ribosomes

Question 34

The outer membrane of the nuclear envelope is continuous with

Answer 34

The rough ER

Question 35

Loss of function experiment

Answer 35

When a component from a system is removed and observed what happens to the systems function

Question 36

Gain experiment

Answer 36

Adding a component that is not normally present in a system to see if it is sufficient to form a function

Question 37

Euchromatin

Answer 37

Transcriptionally active chromatin that allows access to dna

Question 38

Heterochromatin

Answer 38

Transcriptionally inactive dna that is tightly condensed

Question 39

Constitutive vs facultative heterochromatin

Answer 39

Constitutive dna is always condensed and no genes are found, whereas facultative dna is not always condensed

Question 40

Allowing access to dna is controlled by

Answer 40

Histone modifying enzymes, chromatin remodelling complexes

Question 41

How are splicesomes formed

Answer 41

Introns are removed by SnRNPS and exons are linked together

Question 42

Order of compacting dna

Answer 42

1. Naked dna 2. Nucleosomes (10-11 nm) no H1 3. Beads on a string 4. 30 nm fiber ( H1 histones condense fiber) 5. Looping of 30 nm fiber 6. High order chromatin folding 7. Interphase chromosome

Question 43

Endosymbiont theory

Answer 43

Structural and genetic similarities between mitochondria and chloroplasts

Question 44

Inhibitory proteins

Answer 44

Competes with activator for the dna binding site

Question 45

In alternative splicing

Answer 45

Introns are spliced out and exons are joined together, while reducing the number of genes needed to express different proteins

Question 46

Lariat loop

Answer 46

A loop-like structure formed during RNA splicing, where an intron is cut and the 5' end is covalently bonded to a conserved adenine residue, creating a "lasso" shape. This intermediate is released after the intron is removed, allowing exons to be joined together to form mature mRNA.

Question 47

Theory of how genome size decreased

Answer 47

Gene loss and transfer of genes to the nucleus

Question 48

Where does chloroplast protein synthesis occurs

Answer 48

Stroma if they are nuclear encoded and cytoplasm if chloroplast encoded