Cells and Tissues

Glandular tissues are one type of epithelial tissue, and their function is to produce material to secrete.

Platelets are fragments of a cell (a megakaryocyte) bound by a membrane.

DNA is double-stranded, while the “D” refers to “deoxy-“.

Guanine (G) must be matched to cytosine (C) and vice versa. Adenine (A) must match with thymine (T). In RNA, uracil (U) replaces thymine; hence U must be matched to A.

Adipocytes are found in fat (adipose tissue) which is a type of connective tissue.

A sperm has 23 chromosomes which is the haploid number. The male that produced the sperm has 46 chromosomes (23 pairs) in their somatic cells – 23 each from the man’s father and mother. When sperm are produced, the 46 chromosome assemble and pair up. The man’s X and Y chromosomes pair up. Each pair of chromosomes then separates so that only one of each pair moves into a new sperm. Which one of the pair ends up in which sperm is a random process. It is possible that an individual sperm has any number of chromosomes between 0 and 23 that originated from the father.

The ATPase pump shifts 3 Na+ out of the cell and 2 K+ into the cell. This disparity in positive charge is the major influence on the resting potential.

Molecules that are soluble in water cannot pass through lipid (fat). So the phospholipids are a barrier. The functions described by B and C are performed by other molecules in the plasma membrane.

“Intercellular” means between cells. So matrix is fibres and ground substance (but no cells).