C. nerve cells.............................
Answer:
<h2>They are classified on the basis of their cell wall composition and as well as by the reaction to the Gram stain test.
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Explanation:
Most bacteria are classified into two main categories
i) Gram positive bacteria and ,
ii) Gram negative bacteria.
They are classified on the basis of their cell wall composition and as well as by the reaction to the Gram stain test.
Gram positive bacteria's characteristics
ii) they have cell walls composed mostly of peptidoglycan.
i) stain purple after Gram staining.
Gram negative bacteria's characteristics.
i) they have cell wall only a thin layer of peptidoglycan and an outer membrane with a lipopolysaccharide component.
ii) stain red or pink after Gram staining.
It- damages the DNA in skin cells and produces genetic defects that can lead to cancer.
Answer:
A. Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decrease in pH. An example is the bicarbonate system in human body.
Explanation:
In nature, buffer is a known to be a solution capable of maintaining the pH of an ionic solution i.e. resist alteration to the acidic or basic content, by neutralizing excess hydrogen ions (H+) or hydroxyll ions (OH-) added to it.
Buffers, with the aid of their weak acid/conjugate base or weak base/conjugate acid, absorb/react with excess hydrogen and hydroxide ions to prevent increases or decrease in pH. An example of buffer in humans is the bicarbonate buffer system in that maintains stable pH in the human blood.
<span>The essential unit of DNA packaging is the nucleosome. A nucleosome consists of a small amount of DNA wrapped up with protein. The proteins that interact with DNA to form chromatin comprise a family of basic (positively charged) proteins called histones. There are five different types of histone protein: H1, H2A, H2B, H3, and H4. Of these, two molecules each of H2A, H2B, H3, and H4 combine to form a histone octamer. DNA wraps around the octamer, making 1 3/4 turns around the protein complex. The amount of DNA associated with the histone octamer is 146 bp. The octamer plus the DNA comprise what is called the nucleosome core. A small stretch of DNA (60 bp) runs between adjacent nucleosome cores, and is known as the linker. A single nucleosome consists of one core plus a linker. The total amount of DNA involved in a single nucleosome is approximately 206 bp. Chromatin therefore consists of DNA wrapped around one histone octamer after another, like a long string of beads.</span>
