Chapter 8 Intro to Metabolism (Glycolysis 8) Flashcards
Metabolism
- what are the two major pathways of metabolism ?
- what is the differnece between catabolism and anabolism ?
- Another terminology for catabolic and anabolic ?
- Pathways that REGENRATE a component ?
- catabolic and anabolic
- Catabolism:** breaks down molecules into smaller units; **Anabolism builds up smaller units into bigger units.
- Degradative and Synthetic
- cycles
- define metabolism based on the book
- Give one example of anabolism ?
- metabolism is the sum of all chemical changes occuring in the cell.
- glycogen from glucose
Metabolism Map
keypoints to remember
- easier to understand through pathways
- each pathways are composed of multienzymes
Catabolic Pathway
- how does the catabolic pathway function ?
- how many stages that the catabolic pathway have ?
- Define the three stages of catabolism ?
- capture chemical energy in the form of ATP from the degradation of energy rich fuel molecules
- Occurs in THREE STAGES
- Hydrolysis,Conversion and Oxidation
Three stages of catabolism
STAGE I.
hydrolysis of complex molecules (polymers to monomers)
Proeteins = amino acids
Carbohydrates = monosaccharides
Fats = Glycerol fatty acids
STAGE II.
Conversion of building blocks to Acetyl CoA
STAGE III.
Oxidation of Acetyl CoA = Oxidative Phosphorylation
Electron Transport Chain (TCA cycle)
Answer this questions to either TRUE or FALSE
- Catabolic pathways are typically reductive and require the reduction of coenzymes such as NAD +
- Catabolism is a convergent process
- False ; Oxidative; requires the oxidation of coenzymes like NAD+
- True
- The oxidation of Acetyl CoA generates large amounts of
- The oxidation of acetyl CoA makes ATP through
- Define this process: “ the flow of electrons from NADH to FADH2 to Oxygen
- ATP
- Oxidative Phosphorylation
- Oxydation of Acetyl CoA
Anabolic Pathways
- in contrast to catabolism (which is convergent) anabolism is ?
- What do anabolic pathways require ?
- requiring energy is called
- Anabolic reactions involve chemical :
a. reductions
b. oxidations
- divergent
- energy
- endergonic
- reduction
METABOLISM REGULATION
- important for moment-to-moment regulation and elicit in rapid responses
- signaling between cells for long range integration (may result as response to gene expression; surface to surface contact
- intracellular communication
- intercellular communication
Second Messenger Systems
- name two of the most widely recognized second messenger systems?
- What second messenger systems are most important in regulating intermediary metabolism
- what is the role of hormones and neurotransmitters in this subject ?
- Calcium/Phosphatidylinositol system
- Adenylyl cyclase (Adenylate cyclase) system
- Adenylyl Cyclase and Calcium/Phosphatidylinositol
- signal detectors
- Adnylyl cyclase: define in three points
- what is GPCR define in three points
- membrane bound enzyme
- converts ATP to cAMP
- chemical signals arre mostly hormones and neurotransmitters
- G-Protein Coupled Receptor
- characterized by extra-cellular ligand-binding domain
- GPCRs’ have seven transmembrane alpha helices and an INTRACELLULAR domain (that interacts with G-proteins)
GDP and GTP
- GPCR contains subunits; what are these subunits called ?
- How are the occupied GPCR mediated ?
- what causes the trigger of replacement of GDP to GTP?
- forms a link chain of communication between receptor and AC
- GTPase activity: results in rapid hydrolysis of GTP to GDP
- G-alpha _ GTP complex: (true or false) are short lived ?
- alpha , beta and gamma
- by specialized trimeric subunits (alpha, beta and gamma)
- Ligand binding
- GDP or GTP
- G-alpha -GTP COMPLEX
- TRUE
p. 95
- An increase in the activity of adenylyl cyclase is caused by
- formed by ONE active receptor
- hydrolysis of GTP to GDP causes inactivation of G-alpha (what is happening in this case) ?
- the recognition of chemical signals that can INCREASE or DECRREASE the activity of AC
- molecules of active G-alpha protein
- dissociation from AC and reassociation with Beta-dimer.
Concept: Glucose Phosphorylation
Phosphorylation (addition of a phosphate group)
- Mammamls have 4 isozymes (I-IV) of the enzyme______________
- One of the three regulatory enzymes of glycolysis ?
- Catalysis of the phosphorylation of glucose to _________________
- Traits of Hexokinase I-III : give three please.
- Traits of Hexokinase IV isozyme: give three please.
- hexokinase
- hexokinase
- glucose -6 - phosphate
- have a low Michaelis constan Km
- have high affinity for glucose
- have low maximal velocity (Vmax)
- is also known as glucokinase
- liver enzymes (parenchymal cells and pancreatic B-cells)
- responsible for glucose “phosphorylation”
Glucokinase vs.Hexokinase I-III
- How do glucokinase** differ from **hexokinase:
- what are the three main regulatory enzymes for glycolysis
- Describe their affinity for glucose
- hexokinase is found in all cellwalls
- Glucokinase is hexokinase IV found in the liver
- Hexokinase: one of the regulatory enzymes of glycolysis
- hexokinase I-III and hexokinase IV
- phosphofructokinase
- pyruvate kinase
Affinit for glucose
- glucokinase: low affinity for glucose
- hexokinase high affinity for glucose
- The conversion of glucose to pyruvate occurs in how many stages ?
- what part of glycolysis corresponds to energy-investment phase ?
- The next subsequent stages of glycolysis corresponds to
- The energy-generation phase yeilds how many molecules ATP per each glucose metabolized ?
- two stages
- first five stages of glycolysis
- energy-generation phase
- two molecules of ATP per glucose metabolized
EFFECT OF
- ACTIVATED GPCR
- INACTIVE GPCR
ACTIVATED
- mediated by alpha, beta and gamma subunits
- alpha “boy” binds to GDP or GTP
INACTIVE
- Alpha binds to GTP
- GDP to GTP ( transition)
- GTP dissociates from B, Y and moves to Adenylyl Cyclase
What is the rate limiting step for glycolysis ?
Phosphofructokinase - 1