Question

Can someone help me? I'm in Biology9.
3. What is formed at the end of meiosis? (1 point)

Answer 1

two genetically identical cells
four genetically different cells
four genetically identical cells
two genetically different cells

Answer 2

wat unittt and lessson

Answer 3

u in CA?

Answer 4

yes

Answer 5

U4 L18. its the practice thing

Answer 6

I need some help with some other stuff if you can.

Answer 7

ok lemma check if i did it..........

Answer 8

ok

Answer 9

srry im in unit 4 lesson 13 :(

Answer 10

aww. ill post the answers when im done. do u need help with anything?

Answer 11

yea
lol lesson 13

Answer 12

hold on. bio right?

Answer 13

goin into my gb now

Answer 14

Multiple Choice
1. Which of the following statements is true about gene regulation in prokaryotes? (1 point)
(0 pts) Promoters determine whether a gene is expressed.
(0 pts) Expressed genes make more DNA.
(1 pt) DNA-binding proteins determine whether a gene is expressed.
(0 pts) RNA polymerase regulates gene expression
1 /1 point
2. A lac repressor turns off the expression of the lac genes by (1 point)
(0 pts) binding to the promoter.
(0 pts) binding to DNA polymerase.
(1 pt) binding to the operator.
(0 pts) binding to the lac genes.
1 /1 point
3. When E. coli is grown on glucose, and there is no lactose available (1 point)
(0 pts) lactose molecules bind to the lac repressor.
(1 pt) the lac repressor binds to the operator of the lac operon.
(0 pts) RNA polymerase binds to the promoter of the lac operon.
(0 pts) the lac genes are transcribed into messenger RNA.
1 /1 point
4. What is the function of the operator in an operon? (1 point)
(1 pt) Provide a site on the DNA where the repressor can bind and stop transcription.
(0 pts) Provide a site on the DNA where RNA polymerase can bind to begin transcription.
(0 pts) Code for the repressor protein.
(0 pts) Code for the RNA polymerase protein.
1 /1 point

Answer 15

ok

Answer 16

there ya go

Answer 17

thanks lol

Answer 18

is that all jessica?

Answer 19

hello

Answer 20

ok how bout lesson 14 plzzz

Answer 21

ok

Answer 22

im wont give u the exact answers im just gonna help

Answer 23

thanks

Answer 24

my slow teacher is still grading it, i think i rememmber the multiple choice ones tho

Answer 25

yaay

Answer 26

lol, gimme a minute

Answer 27

regulation of the gene right?

Answer 28

yea

Answer 29

I think all of the above for the first one.

Answer 30

argh two headed monster!

Answer 31

lol

Answer 32

I don't really know.

Answer 33

sorry jess

Answer 34

ur behind huh?

Answer 35

do u know this

8. If a mutation occurs in the gene for the lac repressor and results in a repressor that does not bind lactose, which of the following will be observed? (1 point)
The mutant will not be able to grow on lactose.
The mutant will only be able to grow on lactose.
The mutant will be able to grow on lactose and on other sugars.
The mutant will be harmed by the presence of lactose.

Answer 36

no

Answer 37

that sux

Answer 38

Not sure how many questions are actually there, but here you go:
1. four genetically different cells. During meiosis genes from the maternal cell and the parental cell does a switcheroo and therefore the cells will contain different genes.
During meiosis 4 cells are created from 2 cells.

8. Only guessing: The mutant will not be able to grow on lactose.

Answer 39

For question #8, a little background - the lac operon is a set of genes used by bacteria to metabolize lactose and use it for energy/nutrients. In such bacteria, glucose may be the normal energy source, and genes of the lac operon are not transcribed (due to the action of the lac repressor). This prevents the bacteria from wasting resources manufacturing unnecessary proteins (an energy-expensive process).

However, in an environment where lactose is available but glucose is not, the lac operon is activated by removal of the lac repressor, and lactose can then be metabolized by the cell. The lac repressor is removed upon binding lactose, which stabilizes it in a conformation that does not bind to DNA and in this way allows transcription to proceed.

Now to answer the question (@Comrad, @jessica90210): if there is a mutated lac repressor that cannot bind lactose, it cannot dissociate from the lac operon, even in a lactose-rich environment. This means genes whose products are involved in lactose metabolism are not transcribed, and so the bacteria will be unable to grow on lactose alone.

@tyteen4a03, you were right :) Hopefully this explanation helped everyone out, but let me know if I need to clarify anything. I've done university-level courses in molecular biology and microbiology, so I'm happy to help with other questions you may have!