Biology Test 119

When nucleotides are incorporated into 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. In this manner, each strand of DNA has a backbone of phosphate-sugar-phosphate-sugar-phosphate.

A bacterium with numerous flagella all around is known as peritrichous

Sperms are thought to retain fertilising capability for upto 1-3 days once they have entered the female genital tract.

non-fibrous connective tissue include adipose tissue and blood. Adipose tissue gives "mechanical cushioning" to the body, among other functions.

For particles with an aerodynamic diameter less than 1 µm, Brownian diffusion is a major way for deposition in airways where the bulk flow is very low or absent.

One of the distinctive characteristics of most bacteria and other prokaryotes, is a unique cell wall. The only bacterium that has no cell wall is mycoplasma.

Enamel is secreted from ameloblasts, which are derived from oral epithelium tissue of ectodermal origin.

Cystadenomas are formed from cells outside of the ovary. These cysts can become more painful due to a thick, gel-like substance that causes it to grow in size.

Shotgun cloning (also known as the shotgun method) is a method to duplicate genomic DNA. The DNA to be cloned is cut using a restriction enzyme or by randomly using a physical method to smash the DNA into small pieces. These fragments are then taken together and cloned into a vector.

Epiphytic plants hang in air, so they cannot absorb water from soil. The velamen of an orchid is many cell layers thick and capable of absorbing atmospheric moisture and nutrients. It also protects the underlying cells against damaging UV rays. It is an important adaptation of epiphytic orchids.