Biology

I need help with my Biology assignment:

1. One condition that seems to lead to senescence and not apoptosis in stem cells is

a. shortening of telomeres below a critical limit

b. base damage to DNA

c. unequal division of chromosomes at anaphase

d. none of the above

2. Knowing that even in the oldest people’s stem cells seem to have many cell divisions left to them when cultured in vitro (in a dish), the you might contend that a possible reason for that was

a. Absence of inhibitory factors found in the old bodies in the new culture medium

b. factors in the cellular environment of old people’s bodies

c. The presence of high levels of growth factors in the culture serum

d. All of the above

3. In 1962, Leonard Hayflick conducted an experiment that supported Weismann’s Theory of programmed death. He proposed The Hayflick Limit which can be reached faster by:

a. Increasing the rate of cell division

b. Underfeeding cells

c. Decreasing the rate of mutations

d. Synthetically elongating telomeres.

4. The antagonistic pleiotropy theory of aging assumes that each gene has only one effect on the phenotype of an organism at different stages of its life. True or False

5. In Conboy’s study on heterochronic parabiotic pairs, which phrase described what future studies should focus on according to the results of this study?

a. adult stem cells

b. changes in aging cells

c. muscle cell regeneration

d. changes in aging plasma

6. Briefly explain what happened to old stem and progenitor cells in a young systemic environment.

7. Which substance is the most common in cells?

a. carbohydrates

b. salts and minerals

c. proteins

d. fats

e. water

8. Describe how an enzyme may change the transcription patterns of a cell by adding chemical groups to histone proteins. What is this called?

9. Acetyl L-Carnitine/Alpha lipoic acid are ____________ that are produced naturally by the body in _______

a. Amino acids, large amounts

b. Antioxidants, small amounts

c. Toxins, abundance

d. ROS, trace amounts

10. Most genes that determine lifespan in C. elegans are directly in DNA repair. True or False

11. What is the preferable study group in mammalian testing of aging interventions Mice or monkeys? Why?

12. If you were to run a retirement community what would you do to improve the health/lives of the people who depend on you?

13. The ____________ ____________ theory , states that there exists a biological clock and a time dependent plan or program that directs a limitation to a lifespan?

a. DNA damage

b. Evolveabity Theory

c. Mutation-accumulation

d. free radical

14. Unlike inorganic objects like rocks or even computers (at present) , living organisms can repair damage or rebuild or even recycle damages at the sub-cellular level. Give three

instances cellular systems involved in repairing cellular damages.

15. . An often given example of antagonistic pleiotropy, and seems to fit the definition is

A. Cellular senescence

B. Apoptosis

C. Cellular reproduction

D. None of the above

16. In general stem cells ability to reproduce (proliferate) declines with age? True or False

17. Studies using micro arrays have the benefit that

a. they are automated

b. they are quantitative

c. they examine thousands of genes simultaneously

d. they do everything on the lines above

18. Studies of transcription patterns across an animal’s lifetime only make sense if

a. the animals were born at the same time

b. the rates of transcription are identical

c. the same tissues are examined each time

d. protein synthesis mirrors transcription

19. What are the effects of senescent cells on the aging body, why don’t they have the same effects in young bodies?

20.The experiments in heterochronic (cross-age) transplantation showed that

a. younger stem cell populations flourished when transplanted into old recipients

b. stem cells derived from older donors proliferated faster than young stem cells in a young animal

c. the age of the recipient was more important than the age of the donor in a cross-age transplantation experiment

d. none of the above

21. What was surprising in the results of the longitudinal studies of Chambers et al. (and earlier Rossi et al) in which microarray analysis of hematopoietic stem cells revealed that might

make some people doubt that living systems strive for homeostasis ?

22. What do the studies of such progerias as Huntington-Gilford progeria and Werner’s syndrome tell us about normal aging? Explain

23. Here are three quotes from an printed interview with Francis Collins (look him up),

i. ” Collin’s lab team found that in cells growing in the lab, when they used a chemical to un-cap the chromosome ends, it altered gene splicing and led to progerin production and

cellular senescence.

ii. “It’s clear that progerin turns on as a cell is approaching senescence,” Collins said.

Collin’s lab team found that in cells growing in the lab, when they used a chemical to un-cap the chromosome ends, it altered gene splicing and led to progerin production and cellular

senescence.

iii. “While I can’t prove it, it seems likely that progerin itself is part of normal, programmed senescence,” Collins said. “If we understood that, maybe we would be able to come up with

a strategy to deal with the process of normal aging.”

a) We’ve heard that before, that gene splicing alters with age – what does that mean?

b) According to statement ii, they were comparing artificially made senescent cells to the cells of people with what condition?

c) When stating that progerin production is part of normal aging, what theory of aging is he implicitly endorsing?n Why?

24. Describe what you feel are the major ’causes’ of aging – and how that fits into what you think is the correct theory of aging.

25. Where would you direct efforts in aging research?

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