Lecture 3 - Nucleus

Question 1

What are Western Blots?

Answer 1

The gold standard to detect specific proteins from cells or tissues
ALSO USED FOR protein quantification, cell fractionation, post-translational modification, and immunoprecipitations

Question 2

how can you separate cellular organelles?

Answer 2

using a centrifuge at different forces to see: nuclei sediment, mitochondria, lysosomes, peroxisomes), (fragments of plasma membrane & ER sediment),

Question 3

The Nuclear envelope is contiguous with the endoplasmic reticulum….

Answer 3

proteins and lipids have direct access to the nuclear envelope

Question 4

The nucleus and ER may have arisen during evolution by…

Answer 4

invagination of the plasma membrane in ancestral archaea

Question 5

What advantages does the genome enclosed inside the nucleus have?

Answer 5

physical protection, protesction from viruses, more complex regulation via compartmentalization

Question 6

DNA is a template for what?

Answer 6

transcription of RNA

Question 7

what functions does RNA have?

Answer 7

mRNA, rRNA, tRNA, RNA primers, ribozymes

Question 8

Which is NOT true about the nucleus?
A. Contains nearly all the cell’s DNA.
B. Make DNA from DNA.
C. Make Protein from RNA.
D. Make RNA from DNA.

Answer 8

make proteins from RNA

Question 9

what is the central dogma?

Answer 9

transcription, replication, and translation

Question 10

What nucleotides do?

Answer 10

Are the building blocks of DNA (A, T, C, G) DNa also is made of phosphate and sugar

Question 11

what protein production step(s) happens in the nucleus?

Answer 11

transcription and replication

Question 12

what protein production step(s) happens outside the nucleus?

Answer 12

Translation

Question 13

humans have how many pairs of chromosomes?

Answer 13

23

Question 14

what is a chromosome?

Answer 14

a single very long molecule of double-stranded DNA

Question 15

Does the chromosome occupy its own territory in the nucleus?

Answer 15

yes, each one

Question 16

what is it called when the cell is in a resting phase or not dividing?

Answer 16

interphase

Question 17

what is “beads on a string”

Answer 17

a chromatin that is made of linker DNA and core histones of nucleosome

Question 18

what is a chromatin fiber?

Answer 18

packed nucleosomes

Question 19

what does a histone do??

Answer 19

holds the DNA to the nucleosome

Question 20

Can euchromatin and heterochromatin can be present in the same chromosome?

Answer 20

True

Question 21

Define heterochromatin

Question 22

define euchromatin

Question 23

what is the nucleolus/nucleoli?

Answer 23

The site of ribosome synthesis

Question 24

How do proteins and RNA get in/out of the nucleus?

Answer 24

through nuclear pore complexes

Question 25

define pore complexes

Answer 25

a gel-like meshwork of nuclear pore proteins blocks larger proteins and RNA from passively diffusing in/out of the nucleus

Question 26

what is nuclear import?

Question 27

Define the nuclear lamina

Answer 27

cytoskeleton intermediate filaments lining the inner nucleus envelope

Question 28

Nuclease digests the beads on a string, what is the sequence?

Answer 28

chromatin -> nucleosome -> histone and DNA double helix

Question 29

histone H1 does what?

Answer 29

holds chromatin "beads" together for denseness

Question 30

chromatin fiber is a section of a _______

Answer 30

chromosome

Question 31

cohesins do what

Answer 31

create small DNA loops by binding

Question 32

how do clamp proteins work?

Answer 32

ATP hydrolysis enlarge the loops and when the clamps come together it stope further looping

Question 33

what do condensins do>

Answer 33

form loops with the loops

Question 34

where do ribosomal subunits sythesize?

Answer 34

in the nucleus