Question

4. Draw and label a generic structure of an amino acid

5. Contrast and compare DNA and RNA in at least 3 ways

6. Briefly define negative and positive feedback and give a brief example of each

Answer 1

Answer

4) Structure of amino acid

5)  

DNA	RNA
It is deoxyribonucleic acid It is double stranded structure	It is ribonucleic acid It is single stranded structure
The nucleotide bases includes : - Thymine - Adenine - Guanine - Cytosine	The nucleotide bases includes : - Uracil - Adenine - Guanine - Cytosine
DNA is present in the nucleus of the cell	RNA is synthesized in nucleus, but is found in the cytoplasm of the cell

6)

Positive feedback

• When a stimulus triggers response that amplifies the original stimulus, it is known as positive feedback.
• Example : During labor, uterine contractions triggers release of oxytocin from posterior pituitary gland.
  - Oxytocin hormone further stimulates more vigorous contractions to deliver the baby.

Negative feedback

• When a stimulus triggers response that inhibits the original stimulus, it is known as a negative feedback.
• Example : When body temperature rises, hypothalamus stimulates sweating.
  - Evaporation of sweat leads to cooling of the body surface decreasing the temperature.