Biology Questions

True, Stress is a factor that contributes to heart disease risk.

More factors that contributes to heart disease risk are blood pressure, cholesterol, smoking, physical inactivity and overeating.

Goosebumps are caused by the contraction of the tiny muscles attached to hair follicles. These muscles are arrectores pilorum muscles.

The given statement "All bones stop growing by the end of adolescence" is a FALSE statement.

A chromatid is one copy of a newly copied chromosome which is still joined to the original chromosome by a single centromere.

The two identical copies—each forming one half of the replicated chromosome are called chromatids.

Chromonema is the fibre-like structure in prophase in the primary stage of DNA condensation. In metaphase, they are called chromatids.

Yes, plant cells have Mitochondria.

While plant cells have chloroplasts to photosynthesize, they also require ATP for cellular functions, and do use oxygen to break down some of the sugar they produce in order to generate that ATP. They need mitochondria for this.

In particular, at night when there is no light, plants undergo cellular respiration since there is no sunlight to photosynthesize.

They do, however, produce far more sugar and oxygen through photosynthesis than they use up in respiration.

We know that the circulatory system of our body is a loop. The Heart is the pump, the arteries and their smaller branches (arterioles) carry oxygen rich blood all through your body tissues from the heart and the veins and their smaller branches (venules) carry oxygen depleted blood and waste products back to the heart from all the body parts.

In DNA, adjacent nucleotides are linked by a phosphodiester bond: a covalent bond is formed between the 5' phosphate group of one nucleotide and the 3'-OH group of another.

Hence, in this manner, each strand of DNA has a "backbone" of phosphate-sugar-phosphate-sugar-phosphate.

A RNA copy of a DNA gene is called as messenger RNA or mRNA. mRna is used in translation because information is translated from one language (nucleotides) into another (amino acids).

Hence, mRNA is used to transfer genetic information by a cell.