Molecules, Cells, and
Theories - Notes (Changes and
Suggestions in blue and green - 3/6/06)
1. Explain the importance of chemistry and chemical reactions.
- make up all body substances
- perform all body activities
- provide energy for all body activities
2. Explain the importance of cells, proper cell structure and functioning.
- cells and substances they produce make up all
body parts and perform all body functions
- abnormal or unfavorable conditions for cells result
in abnormal or unfavorable body structure and functioning
3. Describe the hierarchy of structure and functioning in the body.
- cells are grouped with similar cells to form tissues, which are combined to form organs, which are combined to form systems, which are combined to form the individuals person
4. Name important body chemicals and list their main functions
- water - solvent, lubricant, cushion, temperature
regulation, cell shrinking and swelling (osmosis), acid/base balance
- carbohydrates = single sugars or chains of sugars -
energy, building materials, cell receptors
- nucleic acids = single nucleotides or chains of
nucleotides (e.g., ATP, DNA, RNA) - individual nucleotides carry energy, chains
provide information that directs cells activities (i.e., genes, protein
synthesis for structure and regulating enzymatic reactions)
- proteins = chains of amino acids - building
materials, receptors, hormones, enzymes, antibodies
- lipids = diverse types of molecules (e.g., glycerides,
phospholipids, steroids) - energy, building materials, hormones
- molecular complexes = glycoproteins,
mucopolysaccharides, lipoproteins - building materials, communication,
transport of materials
- free radicals = atoms or molecules with an unpaired
electron - regulating body functions, defense activities
5. Describe methods of formation of, harmful effects from, and body defense mechanisms against free radicals.
- formed during normal body reactions (e.g.,
signaling, energy production, lipid chain reactions) and
when a free radical damages a molecule
- cause oxidation = damage to nucleic acids, protein,
and lipids -> damage to cells and secretions from cells -> damage to body
structure and functioning
- body defense mechanisms reduce free radical
production, remove free radicals, and repair oxidative damage from free
radicals
6. Describe methods of formation of and harmful effects from glycation.
- glycation = binding of glucose or other sugar
molecules to amino acids and to proteins - > advanced glycation end-products
- cause distortion of proteins, promotion of free
radical formation and oxidative damage, reduction in defense mechanisms against
free radicals, promotion of age-related abnormalities and diseases (e.g., high
blood pressure, atherosclerosis, Alzheimer's disease, diabetes mellitus)
7. List main parts of cells and their functions.
- cell membrane - hold cell together, regulate
entry and exit of materials, receive messages
- cytoplasm - supports parts, produces and stored
substances, provides energy
- endoplasmic reticulum - compartmentalizes cells,
manufactures lipids and proteins
- Golgi apparatus - collects, packages, and exports
materials produced by a cell
- vacuoles - stores substances including enzymes for
defense and digestion within the cell
- mitochondria - interconverts substances, produces
energy, main source of free radicals
- microtubules and microfilaments - provide cell with
support, transport of materials, and movement
- nucleus - houses genetic information as DNA in
chromosomes to control cell activities
8. Explain how genes control cell structure and function and body structure and function.
- 46 chromosomes, each containing many genes
- gene = segment of DNA with a message (e.g.,
instruction to make a protein)
- copy of DNA in form of mRNA carries instruction from
gene to cytoplasm
- ribosomes "read" mRNA to make protein
- proteins make up body structure, regulate production
of other body structural molecules (e.g., carbohydrates, lipids), and regulate
body activities (i.e., as enzymes)
- telomere = end region of a chromosome
9. Describe the main steps in cell reproduction by mitosis.
- cell duplicates DNA in each chromosome
- only part of the
telomere is duplicated, using the enzyme telomerase
- chromosomes are lined up in a row, copies are
separated with one of each moving to opposite ends of the cell
- cell pinches into two portions, each with one set of
chromosomes
10. List reasons why mitosis is important.
- body growth, repair of damaged parts, replacement of damaged or dead cells
11. Describe the Hayflick limit and its possible importance to aging and disease..
- in experimental settings, many types of human
body cells can undergo a limited number of mitoses and then cannot divide
again. This number = Hayflick limit = replicative senescence
- the Hayflick limit decreases as the age of the
person from whom the cells are taken increases
- since the Hayflick limit seems to mimic or
demonstrate aging processes in cells, understanding the Hayflick limit or
controlling it may lead to understanding or control of aging or of certain
diseases (e.g., cancer)
12. Describe neoplasia and its two main forms (i.e., benign neoplasia,, cancer).
- neoplasia = uncontrolled continuous cell
reproduction
- benign neoplasia =
neoplasia that does not spread
- cancer = malignant
neoplasia = neoplasia that spreads
- aging -> increased incidence of neoplasia
- increases in the
number and proportion of elders -> increased incidence and importance of
neoplasia
(See also pp. 66-67 and neoplasias in other body systems)
13. Describe apoptosis and its relevance in aging.
- apoptosis = deliberate programmed cell death
- important during early development, may mimic
certain age changes, unknown relevance in aging
14. Explain relationships between studying aging and studying genetics.
- genes influence or determine XL and ML,
interactions between lifestyle and age-related changes, age-related diseases
(e.g., Alzheimer's diseases, progeroid syndromes, Werner's disease)
- understanding the relationships between genetics and
diseases that mimic aging may lead to better understanding of normal aging
15. Describe the structure and functions of intercellular materials.
- amorphous materials = fluids, gels, and hard
substances
- fibers include collagen (strong, flexible) and
elastin (weak, elastic)
- intercellular materials influence transport of
materials, support, cushioning, binding, body movements, and other physical
properties of the body
16. Distinguish between evolutionary theories of aging and physiological theories of aging.
- evolutionary theories deal with how and why aging
came into existence in living things over eons of time
- physiological theories deal with how an why aging occurs in present day
organisms
17. Distinguish between programmed theories of aging and stochastic theories of aging.
- programmed theories assume that aging is a
planned process with specific causes
- stochastic theories assume that aging occurs because
of chance events
18. List evolutionary theories of aging.
- disposable body theory, antagonistic pleiotropy theory, accumulation of late-acting error theory
19. Describe, compare and contrast the disposable body theory, the antagonistic pleiotropy theory, and the accumulation of late-acting error theory of aging.
- disposable body theory - aging occurs because the
body allocates only enough resources to prevent it to ensure adequate
reproduction. Lack of additional resource allocation allows deterioration of
the body = aging. A stochastic theory.
- antagonistic pleiotropy theory - genes that promote
activities that are helpful in early life promote activities that are harmful
in later life. These harmful effects = aging. A programmed theory
- accumulation of late-acting error theory = harmful
genes that are not allowed to act until later in life have not been eliminated
by natural selection. Over eons, these harmful genes have accumulated through
mutations. The result of their activities = aging. A programmed theory.
20. List and briefly describe physiological theories of aging (genetic, rate of living, free radical, mitochondrial, mitochondrial DNA, clinker, cross-linkage, hormone, calcium, immune system, wear and tear, network) and their relevance to aging.
genetic
genetic
timers
- genetic
biography = genes used in sequence, and 1st part of story = aging
- antagonistic
pleiotropy theory = genes that promote activities that are helpful in early
life promote activities that are harmful in later life. These harmful effects =
aging
- genetic clock =
certain genes monitor age and signal aging to begin
- death gene =
certain gene(s) signal aging in order to produce death
- telomere theory
= loss of telomeres disrupts normal gene activities -> aging
limited gene usage
- somatic mutation
= usage damages genes -> faulty information -> aging
- faulty repair =
decline in DNA repair -> genetic errors -> faulty information -> aging
- error
catastrophe = damage in genetic transcription to RNA or translation to protein
-> cascade of errors -> aging
rate of living theory - normal metabolism causes progressive damage (e.g., free radical damage) = aging. Faster metabolism -> faster aging -> shorter XL and ML.
free radical = free radicals produced by environmental or cell metabolic processes -> damage to cell components (i.e., DNA, proteins, lipids) -> aging
mitochondrial theory = mitochondria produce free radicals and regulate signaling substances. Damaged mitochondria produce more free radicals and do not regulate signaling substances well -> detrimental effects = aging
mitochondrial DNA theory = mitochondrial DNA sustains more damage from free radicals and other causes that does DNA in nuclear chromosomes. Mitochondria with damaged DNA produce less energy and most free radicals -> detrimental effects = aging
clinker = accumulation of harmful chemicals (e.g., lipofuscin, amyloid, glucose) -> damaged functioning = aging
cross-linkage = linking of molecules (e.g., collagen,
glucose) -> improper structure and functioning = aging
- glycation theory = most harmful cross-links
result from glycation from glucose
hormone theories
- hormone imbalance =
decreased regulation of and by the endocrine system (e.g., insulin, growth
hormone, glucocorticoids, reproductive system hormones) -> disruption of
coordination of body functions -> detrimental effects = aging
calcium theory
- declining regulation of calcium concentrations
and movements -> declining regulation of body activities = aging
immune system
- autoimmunity = immune system damages and
destroys normal body components -> aging
- immune deficiency = inadequate immune
functioning -> protection -> damage -> aging
- immune dysregulation = combination of
autoimmune activities plus immune deficiencies plus imbalance of signals from
the immune system to other systems -> detrimental effects = aging
wear and tear
- random accumulation of injuries ->
aging
network theories
- combinations and interactions among two or
more of the other theories
21. Explain why forming and testing theories of aging are important.
- forming testable hypotheses and theories ->
further research -> increased understanding of aging
- once confirmed -> modulation or control of aging;
ability to distinguish aging from environmental, abnormal and disease factors
Copyright 2020: Augustine G. DiGiovanna, Ph.D., Salisbury,
Maryland
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Copyright 2020: Augustine G. DiGiovanna, Ph.D.,
Salisbury University, Maryland
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