The answer would be '<span>A.<span>The genes for melanin pigmentation remain turned on and prepare more melanin than usual to protect the skin from photo-damage when it is exposed to sunlight for long time.'
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Answer:
Clues that can be used to determine whether the movement of solutes through the membrane is passive or active could be the molecule size, membrane potential, and the presence/absence of membrane protein.
Explanation:
Solutes transport through the cellular membrane depends on the solute size, membrane potential, and the presence/absence of integral membrane protein.
There are two types of transport: Active and passive.
- Passive transport: It does <u>not need energy</u>; it is driven by a chemical potential gradient. <u>Small molecules</u> with no charge are transported through the membrane in a gradient favor, from a high concentration region to a low concentration region. There are two types of passive transport: <em>By simple diffusion</em> (small molecules pass through the membrane by themselves) and by <em>facilitated diffusion</em> (molecules are helped by integral membrane proteins to pass through the membrane). In facilitated diffusion, the helping protein can be a <u>channel protein</u> (hydrophilic pores that allow the molecule to pass with no interaction) or a <u>carrier protein</u> (proteins with mobile parts that suffer modification as the molecule pass to the other side).
- Active transport: It <u>does need ATP energy</u> to pass the molecule through the membrane, as they have to <u>move against the electrochemical gradient</u>. This kind of transport is always mediated by a <u>carrier protein</u>. These proteins join with the molecules and suffer changes as they pass the solute to the other side of the membrane. An important example of this kind of transport is the sodium-potassium bomb.
The fetus can be screened for abnormalities using karyotyping and biochemical analysis using amniocentesis and chorionic villus sample.
<h3>What data can we glean from CVS and amniocentesis?</h3>
In at-risk fetuses, these tests can detect genetic illnesses such cystic fibrosis, Tay-Sachs disease, and sickle cell disease. The main benefit of CVS over amniocentesis is that it is done considerably earlier in pregnancy—at 10 to 13 weeks as opposed to 15 to 20 weeks—thus saving more time for the mother.
<h3>What can a couple learn about their growing fetus from amniocentesis and chorionic villus sampling?</h3>
Amniocentesis and chorionic villus sampling (CVS) are prenatal diagnostic techniques used to identify certain fetal genetic disorders. The likelihood of miscarriage rises with both procedures.
To know more about Amniocentesis visit:-
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Answer:
true, the alternative would be postzygotic barriers.
Explanation:
