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3 years ago

How is the plasma membrane of a cell organized?

Biology

1 answer:

liberstina [14]3 years ago

6 0

Answer:

The correct answer is two layers of phospholipids,with their polar hydrophilic heads facing away from each other.

Explanation:

The plasma membrane of a cell contain lipid bilayer.Each monolayer contain phospholipids.The hydrophobic tails of the phospholipid of both the monolayers faces each other in the hydrophobic region where as the hydrophilic heads of the phospholipid molecules of both the monolayers are oriented away from each other.

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Viruses express tissue tropism and host specificity. In particular, the avian influenza strain H5N1 has rare incidences in human

wlad13 [49]

Answer:

Of the mentioned statements, the incorrect one is option D.

Explanation:

The normal H5N1 strain or the bird flu virus when get attached with the alpha 2,3-sialic acid results in the infection of the lower respiratory tract in humans. The condition occurs very rarely. In comparison, the H1N1 or the human influenza strain gets attached with alpha-2,6 sialic acids and easily results in the infection of the upper and lower respiratory tract.

However, if the mutation takes place in the H5N1 strain, it can bind with the alpha-2,6 sialic acid and can result in the overall infection of the human respiratory tract. Now due to the occurrence of mutations in the H5N1 strain, bird flu can get transmit easily from birds to humans and from one human to another human. Also due to lack of immunity because of the emergence of new strain, the condition can become lethal as, like normal flu, the mutated strain can also result in the infection of the entire respiratory tract.

7 0

3 years ago

4. Explain why water is needed in the light reactions.

leonid [27]

Answer:

Light reactions occur when plants synthesize food from carbon dioxide and water, referring specifically to the part of energy production that requires light and water to generate electrons needed for further synthesis. Water provides the electrons by splitting into hydrogen and oxygen atoms.

Explanation:

7 0

3 years ago

Despite his fear of germs, Howard Hughes neglected his own hygiene despite having those around him follow strict cleanliness pra

KATRIN_1 [288]

Answer:

I want to say B. he developed OCD at an old age.

Explanation:

im not entirely sure this is correct so please tell me if its not! hope this helps!

4 0

3 years ago

Read 2 more answers

National parks reduce the human impact on land by _______. a. permitting limited human development. b. cleaning up litter c. pre

lord [1]

Answer – C (Preventing human development)

National parks are mainly established by national governments for conservation purposes, particularly the conservation of 'wild life' for future generations and as an emblem of national pride. National parks reduce the human impact on land by preventing human development.

3 0

3 years ago

Read 2 more answers

If two genes are found on different chromosomes, or if they are far enough apart on the same chromosome that the chance of a cro

nika2105 [10]

Complete question:

A wild-type tomato plant (Plant 1) is homozygous dominant for three traits: solid leaves (MM), normal height (DD), and smooth skin (PP).

Another tomato plant (Plant 2) is homozygous recessive for the same three traits: mottled leaves (mm), dwarf height(dd), and peach skin (pp).

In a cross between these two plants (MMDDPP x mmddpp), all offspring in the F1 generation are wild type and heterozygous for all three traits(MmDdPp).

Now suppose you perform a testcross on one of the F1plants (MmDdPp x mmddpp). The F2 generation can include plants with these eight possible phenotypes:

solid, normal, smooth

solid, normal, peach

solid, dwarf, smooth

solid, dwarf, peach

mottled, normal, smooth

mottled, normal, peach

mottled, dwarf, smooth

mottled, dwarf, peach

Assuming that the three genes undergo independent assortment, predict the phenotypic ratio of the offspring in the F2 generation.

Answer and Explanation:

Cross 1:

Parental) MMDDPP x mmddpp

F1) MmDdPp

Cross 2: Testcross

Parental) MmDdPp x mmddpp

Gametes) MDP MdP MDp Mdp mDP mdP mDp mdp

mdp mdp mdp mdp mdp mdp mdp mdp

Punnet Square)

mdp

MDP MmDdPp

MdP MmddPp

MDp MmDdpp

Mdp Mmddpp

mDP mmDdPp

mdP mmddPp

mDp mmDdpp

mdp mmddpp

F2) 8/64 = 1/8 MmDdPp, solid leaves, normal height, smooth skin

8/64 = 1/8 MmddPp, solid leaves, dwarf height, smooth skin

8/64 = 1/8 MmDdpp, solid leaves, normal height, peach skin

8/64 = 1/8 Mmddpp, solid leaves, dwarf height, peach skin

8/64 = 1/8 mmDdPp, mottled leaves, normal height, smooth skin

8/64 = 1/8 mmddPp, mottled leaves, dwarf height, smooth skin

8/64 = 1/8 mmDdpp, mottled leaves, normal height, peach skin

8/64 = 1/8 mmddpp, mottled leaves, dwarf height, peach skin

Another way of predicting the phenotypic ratio of the offspring in the F2 generation is by performing a testcross for each gene by separately and then multiplying their genotypic proportions. This is:

Leaves Gene

Parental) Mm x mm

Gamtes) M m m m

Punnet Square) M m

m Mm mm

F2) 1/2 Mm

1/2 mm

High Gene

Parental) Dd x dd

Gamtes) D d d d

Punnet Square) D d

d Dd dd

F2) 1/2 Dd

1/2 dd

Skin Gene

Parental) Pp x pp

Gamtes) P p p p

Punnet Square) P p

p Pp pp

F2) 1/2 Pp

1/2 pp

To get the phenotypic ratio of the offspring we multiply the genotypic proportion for each trait by the genotypic proportions of the other two traits, like this:

For plants with solid leaves, normal height, smooth skin

solid leaves ratio -> 1/2

normal height ratio -> 1/2

smooth skin ratio -> 1/2

MmDdPp ratio: 1/2 x 1/2 x 1/2 = 1/8

For plants with solid leaves, dwarf height, smooth skin

MmddPp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with solid leaves, normal height, peach skin

MmDdpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with solid leaves, dwarf height, peach skin

Mmddpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, normal height, smooth skin

mmDdPp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, dwarf height, smooth skin

mmddPp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, normal height, peach skin

mmDdpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, dwarf height, peach skin

mmddpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

3 0

3 years ago