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3 years ago

explain why there are no giant cells. Use the terms diffusion, cell membrane and cell volume in your answer.

Biology

1 answer:

Jobisdone [24]3 years ago

6 0

Answer:

overly large cells have a lower surface area:volume ratio. a large surface area is needed to obtain nutrients, dispose of substances, and for diffusion to occur. A giant cell would not be able to accomplish these tasks effeciently enough, and would eventually die

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Onion root tips are often used to study mitosis because they grow very rapidly, which means that many cells are dividing. The ve

guajiro [1.7K]

Answer:

- Dependent variable: number of cells that are in one of the phases of mitosis

Explanation:

In an experiment, the independent variable is the variable that is not changed by the other variables that are being measured during the experiment (in this case, the independent variable is represented by the distances from the root cap). On the other hand, the dependent variable is the variable that is being measured/tested during the experimental procedure and, therefore, is 'dependent' on the independent variable. In consequence, in an experiment, the dependent variable is expected to change as a result of the manipulation of the independent variable.

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2 years ago

A protein that spans the phospholipid bilayer one or more times is

Leona [35]

Answer:

a transmembrane protein

Explanation:

A transmembrane protein spans the phospholipid bilayer one or more times. they are made of amphiphilic phospholipids: phospholipids with a hydrophilic phosphate head and a hydrophobic tail with two fatty acid chains.

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3 years ago

Explain why both unisexual and bisexual flowers can self pollinate.

rodikova [14]

Answer:

Bisexual flowers:

In order to make a new seed male gamete present in a pollen grain units with the female gamete present in the ovule.

Unisexual flowers:

Unisexual flower can self pollinate where both male and female flowers are present on the same plant. Stigma of the female flower can be pollinated by the pollen of the male flower present on the same plant.

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3 years ago

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imagine a cell-surface receptor protein is being newly synthesized. How can it get into the membrane that it will ultimately be

motikmotik

Answer:

the steps for a new receptor synthesis:

Explanation:

Do not forget the steps vary from an eukarityc cell to prokarityc one.

IN AN EUKARYOTIC CELL:

1- Transcription: in the nucleus, mRNA is synthesized from the DNA sequence that codifies the protein. Exons are spliced if needed by spliceosomes.

2- From nucleus into cytoplasm: mRNA goes through nuclear membrane into the cytoplasm were ribosomes, substrates for protein synthesis and other organelles are.

3- Ribosomes recognize a signal in mRNA and start reading the genetic code, three consecutive nucleotides at a time and adjust the correspondent tRNAs (tRNAs carry the aminoacids)

4- Peptide bonds are formed between consecutives aminoacids, and a polypeptide is build up according to the mRNA sequence.

5- (The mRNA has a signal that is recognized by the rough endoplasmic reticulum) The peptide goes into this reticulum (RER) and then into Golgi apparatus. (more chemical modifications are made if needed). By this moment the protein has an inserted portion in a lipid membrane.

6- The protein is transported in a vessel that finally fusions with cytoplasmic membrane and the receptor is in destiny. Hydrophobic aminoacid sequences are inserted in membrane.

IN A PROKARYTIC CELL:

1- Transcription (no splicing is needed, there are not exons)

2- There are not nucleus and cytoplasm divided (no transport)

3- Ribosomes recognize a signal in mRNA and start reading the genetic code, three consecutive nucleotides at a time and adjust the correspondent tRNAs (tRNAs carry the aminoacids)

4- Peptide bonds are formed between consecutives aminoacids, and a polypeptide is build up according to the mRNA sequence.

5- The mRNA has a signal that is guides the growing protein to cellular membrane. Hydrophobic aminoacid sequences are inserted in membrane.

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3 years ago

What is the significance of secondary growth in plants?

kipiarov [429]

The correct answer is A.
Secondary growth in plants allows many woody and non woody plants to grow tall and strong. The growth basically occurs in the roots and the stems and it is controlled by lateral meristem. Examples of non woody plants that undergo secondary growth include: carrot, potato, tuber, etc.<span />

4 0

3 years ago

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