metabolisim Flashcards
metabolism
the sum of all biochemical reactions that occur in the body.
catabolism
Breakdown larger/complex organic molecules into smaller ones
release energy in form of atp
anabolism
Use simple molecules/monomers to make larger organic molecules
consume energy
Structural maintenance or repairs
Support growth
Produce secretions
Store nutrient reserves
BMR
basal metabolic rate
basal metabolic rate
minimum resting energy expenditure of an awake, alert person.
energy intake =
BMR + Physical activity + Thermogenesis
influences on BMR
Sex – BMR is lower in females- except in pregnancy
Age – BMR is faster in children
Body temperature – increased temperatures speed up BMR
Exercise – increases BMR by 15–20x
Hormones – the sympathetic nervous system increases rate of metabolism
influences on physical activity
type
time
type= aerobic reduces fat
anerobic= builds muscle
influences on thermogenisis
Dietary-induced thermogenesis - increased body temperature required during digestion
Adaptive thermogenesis - increased thermogenesis to cope with temperature changes
Dephosphorylated
Releases energy
Cells use this energy to carry out anabolic reactions
Phosphorylated
Energy is stored in the ATP molecule
Cells can use this energy for future cellular functions
metabolism of carbs
must all be formed into glucose
Catabolism to yield ATP
Amino acid synthesis
Glycogen synthesis
Triglyceride synthesis
glycolysis
location: cytosol
oxygen: not required
net production of ATP: 2
PROCESS: here glucose is broken down in cytosol into pyruvate acid (2 molecules)
krebs cycle
location: mitacondrial matrix
oxygen: is required
net production of ATP: 2
process: 1 glucose → 2 ATP + 4 CO2 + 6 NADH + 6 H+ + 2 FADH2
here pryuvate is broken down into acteyl coa- which then forms carbon dioxide
electron transport chain
location: cristae of mitacondria
oxygen: is required
net production of ATP: 26-28
process: Electrons passed along the chain generating ATP by pumping of hydrogen ions (H+); known as chemiosmosis
Final electron acceptor is oxygen
water is produced
ATP PRODUCED IN RESPIRATION
Glycolysis: 2 ATP (net gain)
Kreb’s cycle: 2 ATP
Electron transfer: 26-28 ATP
Total yield: 30-32 ATP
Provides 16 kJ per gram
glycogenlysis
stored glycogen in hepatocytes release glucose into blood
glycogenisis
Glycogen: glucose molecules joined together
Allows for storage of glucose in the liver and skeletal muscle cells
glyconeogenisis
Production of glucose when blood glucose level is low
Generation of ATP from non-carbohydrate sources
lypolysis
1 Glycerol – enzymes in the cytosol convert glycerol to pyruvate, which then enters the Kreb’s cycle
3 Fatty acids – converted to acetyl-CoA and enters Kreb’s cycle
lypogenisis
Occurs in the liver
Glucose or amino acids can be converted into glycerol and fatty acids and assembled into triglycerides
Stimulated by insulin
Some fatty acids cannot be synthesised in the body
proteinlysis
Worn out cells are broken down to release amino acids which are recycled into new proteins
Liver cells can convert amino acids into fatty acids or glucose
During starvation the body can break down protein
proteinogenisis
Formation of peptide bonds between amino acids to produce proteins
Occurs in the ribosomes
Requires energy
Under direction of DNA and RNA
catabolic hormones
glucagon
cortisol
adrenaline
anabolic hormone
insulin
glucagon
made in alpha cells of pancreasas
Released when blood glucose levels (BGL) are low. It stimulates the breakdown of glycogen in the liver
cortisol
adrenal glands
Released in response to stress. It increases BGL by gluconeogenesis.
adrenaline
adrenal glands
Released in response to activation of the sympathetic nervous system. It stimulates gluconeogenesis and lipolysis, mobilising stored energy reserves
insulin
beta cells
Released when BGL are high. It promotes the uptake of glucose into muscle, adipose tissue and the liver.
absorbitive state vs post-absorbitive
absorbitive glucose used straight away
post- stored as glucagon
