The following diagram represents a cell inside a flask of media:

What is the importance of feedback signals at key checkpoints within the cell cycle?

grigory [225]

to delay or trigger the next phase of cycle

6 0

3 years ago

The force required to prevent the movement of water across a selectively permeable membrane is __________ pressure

SOVA2 [1]

The force required to prevent the movement of water across a selectively permeable membrane is osmotic pressure. The plasma membrane forms a vesicle around the substances to be transported, and the vesicle around the vesicle is taken into cells.

Osmotic pressure depends on both the pressure gradient and concentration gradient. This is only affected by the temperature and concentration of solute, each affect the movement of water across a membrane.

Higher the concentration is higher temperature increases osmotic pressure, which produced or associate with osmosis and dependent on molar concentration and absolute temperature. Hydro-static pressure forces fluid out of the capillary , osmotic pressure draws fluid back in.

To learn more above the Osmotic pressure here

brainly.com/question/15501096

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5 0

2 years ago

In corn, small pollen (sp) is recessive to normal pollen (sp+) and banded necrotic tissue, called zebra necrotic (zn), s ssive t

alex41 [277]

Answer:

Option B

Explanation:

Please see the attached image

Given -

Allele for small pollen is "sp"

Allele for normal pollen is "sp+"

and "sp+" is dominant over "sp"

Allele for zebra necrotic tissue is "zn"

Allele for normal necrotic tissue is "zn+"

and "zn+" is dominant over "zn"

Cross is carried out between

sp+ sp zn+ zn x sp+ sp zn+ zn

The gametes of the parent cells are -

sp+ zn+, sp+zn, spzn+, spzn

The cross would be as follows

sp+ zn+ sp+zn spzn+ spzn

sp+ zn+ sp+ sp+ zn+ zn+sp+ sp+ zn+ znsp+ sp zn+ zn+ sp+ spzn+ zn

sp+zn sp+ sp+ zn+ znsp+ sp+ zn znsp+ sp zn+ zn sp+ sp zn zn

spzn+ sp+ sp zn+ zn+sp+ sp zn+ znsp sp zn+ zn+ sp sp zn+ zn

spzn sp+ sp zn+ zn sp+ sp zn zn sp sp zn+ zn sp sp zn zn

Hence, option B is correct

7 0

3 years ago

Imagine you are investigating the case of a young man who seems not to respond to stressful situations the same way most people

anzhelika [568]

Answer:

The answer of the human body to stress, and stressful situations, including to conditions that may trigger the stress response of the body, is a pretty complex one involving the nervous system as a whole, and the adrenal glands, which are responsible for producing two of the most important stress-related hormones. These hormones: glucocorticoids and corticoids (cortisol), will in turn affect all body systems in different manners to produce the necessary effects, to respond to the perceived "threat".

In essence, we have a pathway from our brains, to our adrenal glands, known as the hypothalamic-pituitary-adrenal (HPA) axis. In this axis, several genes that are geared towards stress responses activate (CRHR1 and CRHR2, among others) and produce CRH (Corticotropic releasing hormone), which in turn is directly related with stimulating the production of cortisol when there is stress. However, because our bodies are not meant to be in a constant state of alertness and preparation, because the different organs of the body are negatively affected, there are also pathways that will turn off this response and lower the stressful production of cortisol.

In this particular person, although he has been exposed to the same stressor as the others, he does not have precisely the same reactions to it as the others. It is important to note one thing here, and that is, that the stressor offered to these people were videos of stressful situations, and what is known about the stress response is that one vital part of it is visual exposure to different factors, including light, and images. These exposures cause the HPA axis to initiate a response through CRH production. However, it seems that in this young man, although most of the responses are present, not all of them are. So one solution could be that he has a mutation in his genes in his HPA axis, and therefore CRH is not being produced in enought levels to stimulate sufficient levels of cortisol production. However, there are also other genetical reasons why, and these could be many.

6 0

2 years ago

According to the endosymbiotic theory, which organelles were believed to be once simple prokaryotic cells?

g100num [7]

D. Mitochondria and Chloroplast

i'm sorry if it's wrong but that should be the right answer

4 0

3 years ago