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1 year ago

The ara operon is controlled by a regulator protein that exerts ________.

1 answer:

7 0

AraC protein certain to the ara operator works as a repressor that avoid transcription of the same ara operon and the araC gene AraC protein is an activator in the presence of arabinose and repressor in the absence of arabinose -With arabinose absent, the AraC protein stays as
a homodimer. One AraC protein put together to the ara initiator and the other protein now binds to a different regulatory site in DNA called the ara operator.

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"Which statement best describes the method used above to determine the evolutionary relationships between three species of finch

kiruha [24]

The method used above involves the determination and comparison of the genes of the three species of finches. So, the answer is
<span>(3) Obtain molecular evidence from all three species and identify similarities.
</span><span>The genetic makeup of the three species will show different similarities that can be used to relate the evolution of the different species.</span>

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2 years ago

Complete the following analogy regarding cell division.

Georgia [21]

Reproduction of a cell from an existing cell

4 0

2 years ago

Which statements in this passage about volcanoes do not contain factual errors?

belka [17]

Answer:

The correct answer is option 2. "Scientists use seismometers to measure the earthquake activity that occurs beneath a volcano. They then predict the eruption of that volcano".

Explanation:

A seismometer is an equipment used by scientists to monitor ground's motion, including the earthquake activity that occurs beneath a volcano. These instruments are useful to predict if a volcanic eruption is imminent. By analyzing the length and strength of the ground's motion occurring during earthquake activity near a volcano, scientist could predict if an eruption is about to take place.

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1 year ago

Compare and contrast the differences between mature human eggs and sperm in the following questions. For each prompt, determine

Llana [10]

Answer:

QUESTION 1:

a. They undergo unequal cytoplasmic division during meiosis- eggs

b. Their chromosomes have undergone genetic recombination and independent assortment- both gamete types

c. They contain specialized secretory vesicles called cortical granules just under the plasma membrane- eggs

d. They are characterized by a flagellum. Most of these gametes die without ever completing meiosis- sperm

e. The acrosomal reaction occurs in these cells- sperm

f. They can be derived from any adult cell type- neither gametes

QUESTION 2:

c) The egg is surrounded by a mineralized shell added before the egg exits the body.

Explanation:

a) Female reproductive cells undergo meiosis to produce one large egg and three polar bodies. However, an unequal cytoplasmic division occurs in favour of the large egg.

b) Since both egg cell and sperm cell are produced via meiosis and meiotic division involves the processes of genetic recombination and independent assortment, hence, both gamete types have their chromosomes underg genetic recombination and independent assortment.

c) Egg cells contain specialized secretory vesicles called cortical granules just under the plasma membrane. This cortical granules help prevent more sperms from fertilizing the same egg after it has been fertilized.

d) Sperm cells possess flagellum for motility in the female reproductive tract. Most of the sperm cells die without ever completing meiosis.

e) Sperm cells possess an head-covering structure called ACROSOME. Acrosome reaction is the process undergone by sperm cells permeate the zona pellucida of the egg.

f) Gametes are specifically derived from adult reproductive cells and hence, NEITHER TYPE OF GAMETE can be derived from any adult cell type

QUESTION 2:

The egg in Sea urchins is surrounded by a mineralized shell added before the egg exits the body to the external environment. This does not occur in the humans because the egg does not leave the body but fertilized internally.

8 0

2 years ago

A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the ot

Anni [7]

Options for the question have not been give. They are as follows:

A. P site

B. A site

C. E site

D. directly to the cytosol

E. exit tunnel

Answer:

C. E site

Explanation:

Translation is the process by which mRNA is converted into polypeptide chain. Translation machinery has three binding slots for tRNA : A, P and E. Any incoming tRNA encounters A, P and E site in that order.

When a new tRNA (#1) carrying the next amino acid (here, lysine) comes, it enters the A site. Peptide bond is formed between lysine and the already existing amino acid on the growing polypeptide chain on the preceding tRNA (#2). Once lysine is added to the polypeptide chain, the entire chain moves to tRNA #1 which makes tRNA #2 empty. Meanwhile, the machinery moves forward. As a result, tRNA #1 slides to P site and tRNA #2 slides to E site. The A site is empty now and can receive another tRNA.

4 0

2 years ago