Exam 4: Cellular Aging

The mitotic cell will enter the G₀ phase if there is no end cap on the telomeres.

Because the aging of an organism reflects a gradual decline in function after the reproductive period,the decline and eventual loss of cell division has generally been viewed as characterizing cellular aging;this period is known as:

Initiation of the cell cycle in multicellular organisms appears to occur only when the cell receives an extracellular signal from substances called ______.

Human embryonic cells maintained in culture are immortal.

Oxygen-based metabolism is referred to as ______,and metabolism without oxygen as ______.

Although the mitochondria generate the majority of oxygen-centered radicals,most associated damage occurs in the cytoplasm.

Most of the life of a normal cell is spent in which phase?

The cellular accumulation of damaged biomolecules decreases after sexual maturation.

During prophase,the ______ duplicate and move to opposite sides of the nuclear envelope.

Eukaryotic cells duplicate and divide through an orderly sequence of events defined as:

What structures shorten with each replication cycle?

It is generally accepted that replicative senescence provides a good model for aging of the whole organism.

Oxygen-centered radicals can be used to benefit the organism.

The separation of the double helix to allow new DNA synthesis is divided into thousands of individual reactions starting at sites along the DNA called:

Without the ______ on the end of the telomeres,DNA polymerase reads the ends of the telomeres as strand breaks and initiates the DNA repair mechanism.

The total energy of a biological process is called ______ (H)and equals usable energy (______,G)plus unusable energy (______,S).

Which two vitamins help to prevent the formation of lipid peroxides?

The promoter region of a gene can be located thousands of nucleotides away from the coding region of the gene.

Oxidized compounds have fewer electrons than reduced compounds,making them less reactive.

The telomere-shortening theory is an example of a stochastic theory of cell aging.