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
Loose connective tisue
-adipose tissue=type of loose CT that provides insulation & stores lipids as an e energy source in the hypodermis, bone marrow and fat cells
-reticulalr tissue-forms a meshwork to support body tissues & organs
Supporting connective tissue
-3 types of cartilage in the body
-consists of collageneous fibres imbedded in a firm matrix of chondroitin sulphates
Fluid connective tissue
blood=1 of the CT
-contains erythrocytes & various types of leukocytes that circulate in an EC matrix
lymph=other type of FCT
Muscle tissue
specialised for contraction to facilitate movement, joint stability, structural control, production of heart, ect
List and describe the 3 types of muscle tissue
- Skeletal (attached to bone, contracts to move the body)
- Smooth (forms walls of hollow organs, contracts to move substances/objects through internal passageways)
- Cardiac (forms walls of heart, contracts to pump blood into circulation)
Nervous tissue
-primary function=communication
types:
-neurons (nerve cells)
-neroglia (supports cells/supplys nutrients to neurons)
Membranes
Sheets of flexible tissue that line/cover a part of the body
Most membranes are composed of epithelium and an underlying CT; known as epithelium membranes
Cutaneous membrane
skin-covers the body’s surface
Mucous membrane
Line the digestive, respiratory, urinary and reproductive tracts.
Coated with the secretions of mucous glands
Serous membranes
line body cavities close to the exterior of the body; the peritoneal, pleural and pericardial cavities
Synovial membranes
Line joint cavities and produce fluid within the join
Homeostasis
the body’s ability to maintain a stable (balanced) internal environment in the face of variable external conditions through constant interactions of the body’s many regulatory processes
Equilibrium
constant state of balance required to keep us alive
Hypoglycaemic
not enough glucose in the blood
Hyperglycaemic
Too much glucose in the blood
How does the nervous system maintain homeostasis?
Sends electrical messages (nerve impulses) along nerves to organs that can act to counter the change
How does the endocrine system maintain homeostasis?
Sends out chemical messages (hormones) from the glands into the blood
Controlled condition
variable that is monitored e.g temp, BP, blood glucose
Stimulus
Any disruption to the controlled condition
Receptor
Detects the change and notifies control centre e.g nerve ending
Control centre
sets range and receives information from the receptor.
evaluates and processes the information, determines what action to take and sends output commands to the effector
Effector
receives commands from control centre and produces response
Response
Effect that changes the controlled condition
Negative feedback
when the response opposes the initial stimulus to reverse the change
most homeostatic mechanisms are negative feedback loops
e.g body temp, BP, blood pH, ect
