Neurons (chapter 1 - Part 2)

Question 1

what is the difference between gene expression and protein synthesis

Answer 1

gene expression: reading the DNA
protein synthesis: making the protein

Question 2

if all cells in our body have the same DNA, how is it that they have different shapes and different functions? (example between neurons, gall bladder and smooth muscle)

Answer 2

PROTEINS (the book is the same, but the pages are different. every cell has some copy of the book, but different information on each page)

Question 3

what determines the structure of neurons?

Answer 3

the cytoskeleton (microtubules and all other proteins)

Question 4

what determines the function of neurons? (2)

Answer 4

chemical reactions inside the neurons
-generation of ATP in mitochondria
-synthesis of neurotransmitters

properties of the cell membrane
-Neurotransmitter receptors on dendrites
- Channels in axons required for propagation of signal

Question 5

are all enzymes proteins?

Answer 5

yes!

Question 6

are proteins poly-peptides? and what are poly-peptides

Answer 6

yes, they are. poly-peptides are a long chain of amino acids

Question 7

Name properties that each amino acid has.

Answer 7

-central carbon
-carboxyl group (COO-)
-hydrogen group
-amino group (H3N+)
-variable residue (R-group)

Question 8

what property of an amino acid makes it different from another protein?

Answer 8

the variable R residue

Question 9

what determines the 3D structure of the protein (think of water)

Answer 9

residues can be hydrophobic or hydrophilic, which determines if the amino acids are facing in or facing out, which ultimately determines the 3D structure.

Question 10

Proteins are formed by joining amino acids. What links different amino acids together?

Answer 10

Peptide bonds. More precisely, the carboxyl and amino groups join.

Question 11

in general, what shapes the protein?

Answer 11

The shape of the protein depends on the amino acids that get joined together
-Many combinations of amino acids are possible
-Many shapes are possible

Question 12

how many levels of structure do proteins have? (levels of folding)

Answer 12

4 levels (primary, secondary, tertiary, quaternary)

Question 13

how is the function of a protein determined?

Answer 13

By its shape.

Question 14

What specifies the order of an amino acid in a protein?

Answer 14

DNA

Question 15

please describe how a gene is encodded

Answer 15

-A gene is the sequence of codons (required for a sequence of amino acids) that make up a given protein
-Genes that are activated, determine which proteins will be synthesized

Question 16

what are the two major steps of protein synthesis?

Answer 16

Transcription and translation

Question 17

in general terms, what is transcription? and what happens (simple terms)

Answer 17

DNA TO mRNA

Adenine pairs with Uracil (different from DNA pairs)
Thymine pairs with Adenine
Guanine pairs with Cytosine
Cytosine pairs with Guanine

Question 18

now explain in more detail how transcription works.

Answer 18

Gene transcription. (a) RNA molecules are synthesized by RNA polymerase and then processed into mRNA to carry the genetic instructions for protein assembly from the nucleus to the cytoplasm. (b) Transcription is initiated at the promoter region of the gene and stopped at the terminator region. The initial RNA must be spliced to remove the introns that do not code for protein.

Question 19

after, where does mRNA go?

Answer 19

mRNA leaves the nucleus

Question 20

in general terms, describe the second step of protein synthesis

Answer 20

translation (making the protein)
Proteins made by free ribosomes will stay in the cytosol (e.g.: enzymes).
* Whereas proteins made by
ribosomes in the rough ER
will end up in organelles or the membrane.

Question 21

now describe in detail the process of protein synthesis with different players and roles involved

Answer 21

look at blank page in notes on iPad for full detailed explanation.

Question 22

what happens when the end protein is a massive polypeptide? what do we do and where does it happen?

Answer 22

The final protein is
sometimes cut from a
much larger protein
* e.g. beta-endorphin, corticotropin…

It’s slicing that happens in the golgi apparatus.

Question 23

name a gene that provides instructions for making a protein called FMRP. This protein is present in many tissues, including the brain, testes, and ovaries. In the brain, it may play a role in the development of connections between neurons (synapses).

Answer 23

The FMR1 gene.

Question 24

talk a bit about the genetics of fragile X syndrome

Answer 24

-physical and cognitive changes
-one gene that codes for one protein might be involved in several different functions, thus can cause all sorts of errors/problems/issues