Wk 3: Cell metabolism, tissues and homeostasis Flashcards
What is metabolism
the sum of all biochemical reactions that occur in the body
What are the two types of metabolic reactions?
- Catabolic reactions
- Anabolic reactions
Catabolic reactions
-breakdown of larger/complex organic molecules into smaller ones
-release energy (produce more energy than they use: exergonic)
-used in glycolysis, Kreb’s cycle, electron transport chain and food digestion
-give off heat when larger molecules are broken down into smaller ones
Anabolic reactions
-use simple molecules/monomers to make larger organic molecules
-consume energy (use more energy than they produce: endergonic)
-male protein from amino acids and phospholipids from fatty acids
-use ATP to make larger molecules from smaller ones
Adenosine Tri Phosphate (ATP)
cells “energy currency”
-powers activities e.g muscle contraction, chromosome movement, anabolic reactions ect
-transfers energy released from exergonic (catabolic) reactions to power endergonic (energy requiring reactions)
Describe ATP structure
-3 phosphate groups attached to adenosine (adenine + sugar)
-energy stored in phosphate bonds
-ATPase hydrolyses ATP into ADP + phosphate group, releasing energy stores in the phosphate bond
-ATP synthase catalyses he addition of a phosphate group to ADP to reform ATP
What is cellular respiration?
the oxidation of glucose (removal of electrons and H+ atoms) to produce ATP
Name the 3 sets of cellular respiration reactions
- Glycolysis
- Kreb’s/citric acid cycle
- Electron transport chain (ETC)
Explain everything you know about Glycolysis
- breakdown of glucose
-occurs in the cytosol
-does not require oxygen (anaerobic)
-catabolic process, uses 2 ATP and produced 4 ATP
-glucose becomes 2 pyruvic acids
-if O2 is not available (e.g during strenuous exercise), pyruvic acids then becomes lactic acid/lactate.
-if O2 is available, pyruvic acid enters mitochondria and is converted to acetyl coenzyme A. Acetyl coenzyme A enters the Kreb’s cycle
Explain everything you know about the Kreb’s cycle
-requires oxygen
-acetyl COA enters the Kreb cycle in the matrix of the mitochondria
-kreb’s cycle releases C02
-energy (electrons) transferrred to 2 energy carrying coenzymes, NAD & FAD
-for each turn of the cycle (citric–>oxaloacetic acid): 3NADH, 3H+, 1FADH & 1ATP are produced
-2 turns of the cycle per glucose (2 pyruvic acid) generates 2 ATP
Explain everything you know about the Electron transport chain (ETC)
-requires O2
-on inner mitochondrial membrane, cristae increases S.A
-integral memrane proteins that are electron carriers from a chain in the membrane
-electrons passed through the chain generating ATP by pumping out H+ (chemiosmosis)
-final electron acceptor=O2
-26-28 ATP are produced
How much ATP does each cellular reaction produce?
- Glycolysis (anareobic) 2 ATP
- Kreb’s cycle (aerobic) 2 ATP
- ETC (aerobic) 26-28 ATP
Name 3 examples of metabolism
- Glycogenesis
- Glycogolysis
- Gluconeogenesis
Explain Glycogenesis (synthesis of glucogen)
Glucose storage when blood glucose is too high
-triggered by insulin
-glycogen: many molecules of glucose joined together
-glucose storage in liver and skeletal muscle cells
-formed when not needed to produce ATP inside cells
Explain Glycogenolysis (break down of glycogen)
glucose release from storage when blood glucose level is low
-triggered by glucagon & adrenaline
-when blood glucose levels drop, stored glycogen in hepatocytes release glucose into blood
*skeletal muscles do not release glucose from gylcogenolysis into blood, it is kept for their own use
Explain Gluconeogenesis (synthesis of glucose from non-carb sources)
Production of glucose when blood glucose level is low
-triggered by cortisol & glucagon
-generation of ATP from non-carb sources
-amino acids, lactic acid, glycerol can be used
-60% of body’s amino acids can be used for gluconeogenesis
Tissue
a group of similar cells which carry out specific functions by working cooperatively
tissues work together to form an organ
4 types of body tissues
- epethial (covers)
- connective (supports)
- Nervous (controls)
- Muscle (moves)
Epethial tissue function & structure
-lining of GI tract, organs and other hollow organs, epidermis
-functions: protection, absorption, filtration, excretion, secretion
-Classified by shape and no. of layers
-Avasular-without blood cells
-high rate of mitosis-cells are contantly replaced
Connective tissue structure & function
functions:
-supports and binds other tissues
-provides insulation & protection to internal organs
-protective sheath around skeletal muscles
-classified according to physical properties
-all tissues types expect fluid connective tissues share 3 basic components:
1. specialised cells
2. extra-cellular protein fibres
3. ground substance (material between cells)
Ground substance
stores water and supports cells by bindings them together using proteoglycans and adhesive proteins such as fibonectin
List the 5 types of connective tissue
- Connective tissue proper
- Connective tissues proper (dense: regular & irregular)
- Loose connective tissue
- Supporting connective tissue
- Fluid connective tissue
Connective tissue proper
-large amount of background matrix, protein fibres and some cells
-reticular fibres form a mesh to support the tissue; elastic fibres give the tissue stretch and recoil ability
-fiboroblasts build CT & secrete fibres
Connective tissue proper-DENSE
“dense” indicates CT has losts of collagen fibres
regular:
-large no. of collagen proteins=parallel; provides max tissue strength
irregular:
-large no. collagen; however arranged along different planes
