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2 years ago

A single-celled organism can be classified as a prokaryote based on the absence of-

Biology

2 answers:

Amiraneli [1.4K]2 years ago

6 0

Answer:

A nucleus and membrane bound organelles.

Andru [333]2 years ago

5 0

Answer:

lack of nucleus.

Explanation:

A prokaryote is a simple, single-celled organism that lacks a nucleus and membrane-bound organelles.

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Suppose we discovered a form of life like our own which utilized 20 amino acids, but had 6 nitrogeneous bases instead of the 4 o

mezya [45]

The minimum legth of a codon could be two. If it was only one of the 6 nitrogeneous bases in a codon, we'd only have 6 possible amino acids. If we have, though, a combination of two amino acids out of the 6 nitrogeneous bases, we would have then 36 possible combinations (6 possibilities for the first position × 6 possibilities for the second position) that would allow the existence of the 20 different amino acids.
In the human case, for example, with only 4 nitrogeneous bases, a combination of two amino acids would be insufficient (4×4=16) for the 20 amino acids.

6 0

2 years ago

The karyotype for trisomy 21 illustrates an example of a genetic mutation caused by A) insertion. B) inversion. C) crossing over

Katyanochek1 [597]

Trisomy 21, as illustrated by the karyotype, is caused by nondisjunction. This occurs when chromosomes do not separate properly during meiosis.

Answer is D) nondisjunction

7 0

2 years ago

Read 2 more answers

The epidermis is the most superficial layer of the skin. It is composed of stratified squamous epithelium. Within the epidermis,

son4ous [18]

Answer:

a. Stratum corneum 5. : Thick superficial layer of flat, keratinized, dead cells; responsible for dandruff.

b. Stratum granulosum 3.: Cells flatten and fill with keratin, resulting in a grainy appearance.

c. Stratum lucidum 4. : Clear layer found only in thick skin; cells full of keratin.

d. Stratum basale 1. : Deepest layer; site of rapid cell division and melanin production.

e. Stratum spinosum 2.: Live keratinocytes connected by desmosomes produce pre-keratin

Explanation:

The epidermis has five layers, starting from the deepest one they are:

The stratum basale: is the layer that has the germinative cells, called keratinocytes.

The stratum spinosum: the keratinocytes are connected, and they produce the precursor of keratin and lipids.

The stratum granulosum: the name of this stratum is due to the appearance of the cells. They produce keratohyalin, and the lipids produced in the previous layer are released, creating the layer that protects the skin against dehydration.

The stratum lucidum: They are only in thick skin, like the one that is in the sole of our feet. The cells do not have a nucleus. They are filled with keratin, which is the component of thick skin.

The stratum corneum: the more superficial layer, it is made of dead cells filled with keratine. When new cells ascend to this stratum, the old ones have to be removed by exfoliation or natural peeling.

4 0

2 years ago

Which is a function of mucus in the lungs?

Shkiper50 [21]

Hello There!

The "Lungs" are pairs of organs within the rib cage.

In the "Lungs" the mucus traps dust and pollen

6 0

2 years ago

Read 2 more answers

Which of the following statements about dinoflagellates is true? Select one: A. All known varieties are autotrophic. B. Their wa

Valentin [98]

Answer: The correct option is D(Some produce toxic agents in the water).

Explanation:

Dinoflagellates are found in the phylum Dinoflagellata which are single celled organisms. They are mostly found in the ocean while few of them can live in streams, freshwater ponds and rivers. The following characteristics can be used to identify a Dinoflagellates, these include:

--> they are golden brown

--> they possess assimilative cell with indented waist.

--> they possess large nucleus with visible chromosomes.

It has been reported that many dinoflagellate species can produce various natural toxins. These toxins can be extremely toxic and many of them are effective at far lower dosages than conventional chemical agents. Therefore the option, Some produce toxic agents in the water, is a correct statement.

6 0

2 years ago