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50 Cards in this Set
- Front
- Back
what does metabolism refer to?
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all the chemical reactions in the body |
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what two processes is metabolism split into? |
anabolism and catabolism |
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what is anabolism? |
build up of large molecules from smaller ones |
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what is catabolism?
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break down of large molecules into smaller ones |
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what are the 3 main stages of aerobic respiration? |
- citric acid cycle (Kreb's cycle) - electron transport chain |
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what is required for aerobic respiration to occur? |
oxygen |
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what is produced during aerobic respiration? |
- water - 36 ATP |
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what is glycogenesis?
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glucose storage
|
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what happens to most glucose?
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it is catabolised to make ATP |
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what happens to glucose if it is not needed? |
It combines with many other molecules of glucose to form glycogen (polysaccharide) |
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then what happens to the glycogen? |
it is stored mostly in skeletal muscle fibres and some in liver cells |
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what is this process called? |
glycogenesis |
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what is glycogenolysis? |
glucose release |
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how can glycogen be used if glucose is needed? |
glucose can be formed from glycogen stored in liver hepatocytes and released into the blood stream |
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what is this process called? |
glycogenolysis |
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what can't glycogen in skeletal muscles be used for? |
cannot be released into bloodstream |
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what can it do? |
can be catabolised for ATP production in the cells, and the lactic acid (from glycolysis and Kreb's cycle) can be converted to glucose in the liver |
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what is gluconeogenesis? |
the synthesis of glucose from triglyceride (glycerol) and protein (amino acid) catabolism |
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when does this occur? |
- on a larger scale when people are starving, eating very few carbohydrates or have an endocrine disorder |
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what is the process called?
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gluconeogenesis |
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where is gluconeogenesis performed and by what?
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in the liver by hepatocytes |
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how much energy do lipids yield compared with carbohydrates? |
more than twice as much energy |
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what do triglycerides stored in adipose tissue constitute? |
98% of body's energy stores |
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what does adipose tissue have the advantage of?
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providing insulation and physically protecting from trauma |
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what is continually happening to stored triglycerides? |
continually being broken down, resynthesized and redeposited into other adipose tissue cells
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however, why does the body prefer to use glucose for energy over lipids?
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because fat is more difficult to catabolise than carbohydrates |
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what is lipid catabolism - lipolysis? |
the breakdown of triglycerides into glycerol and fatty acids |
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what happens to glycerol? |
it is converted into pyruvic acid and enters the citric acid cycle to produce ATP |
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what happens to fatty acids? |
they are converted into acetyl coenzyme A (CoA) in the liver, which then enters the citric acid cycle to form ATP |
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when are ketone bodies formed? |
as part of fatty acid catabolism, some long chain fatty acids convert into ketone bodies |
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what kind of quantity are they usually produced in? |
small quantities |
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when does overproduction of ketone bodies occur? |
- uncontrolled diabetes (inadequate glucose can get into cells) |
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what happens to the body with excess ketone body production? |
- cause metabolic acidosis (or ketosis/ketoacidosis) |
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what is a clinical sign of acidosis? |
smell of acetone on breath or ketones present in urine (ketonuria) |
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why is lipogenesis? |
lipid anabolism |
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what occurs during lipogenesis? |
liver cells and adipose tissue synthesise lipids from glucose or amino acids |
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when does lipogenesis occur? |
when more calories have been consumed than are needed |
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what happens to resulting triglycerides from lipogenesis? |
stored or undergo further reactions to produce lipoproteins, phospholipids or cholesterol |
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why is regular protein intake important? |
because amino acids can't be stored |
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why are excess amino acids used for? |
- synthesised to make new proteins - converted into glucose (glyconeogenesis) and triglycerides (lipogenesis) |
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where is the main site of amino acid/protein metabolism? |
the liver |
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what must be removed before ATP can be made from amino acids? |
the NH2 group` |
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what is this process called and what does it produce?
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deamination and produces ammonia (NH3) |
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what happens to highly toxic ammonia?
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the liver converts it to urea to be excreted in urine |
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what is metabolic rate? |
the overall rate at which metabolic reactions use energy |
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what is the basal metabolic rate (BMR)? |
metabolic rate measured under resting/fasting conditions |
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what hormone increases BMR? |
thyroxine |
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what does thyroxine do? |
increases BMR by increasing aerobic respiration |
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how does exercise affect metabolic rate?
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Increases it by as much as 15 times |
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what are some hormones that increase basal metabolic rate?
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- sympathetic ns release of adrenalin and noradrenalin |