Flashcards in 4. Energy Production - Carbohydrates (a) Deck (29)
What is the aim of catabolism?
To produce: organic precursors, reducing power, and energy.
How is reducing power converted to ATP energy?
By oxidative phosphorylation.
What are the four key steps in the overview of catabolism?
1. Breakdown to building block materials.
2. Breakdown to metabolic intermediates and release of reducing power and energy.
3. Kreb's cycle and release of reducing power and energy.
4. Oxidative phosphylation and conversion of reducing power into ATP energy.
What is the purpose of the first stage of catabolism?
To convert nutrients to a form that can be taken up into cells.
Where does stage one of catabolism take place?
Extracellularly in the GI tract.
Where does stage two of catabolism take place?
Intracellularly in the cytoplasm and mitochondria.
Which stages of catabolism are oxidative and which are reductive?
Stage two - oxidative.
Stage three - oxidative.
Stage four - reductive.
Where does stage three of catabolism take place?
In the mitochondria.
Which stages of catabolism produce energy?
Some produced in stage two and three and lots of energy is produced in stage four.
Where does stage four of catabolism take place?
What are the two main things that happen in stage four of catabolism?
Electron transport and ATP synthesis.
What's the general formula of carbohydrates?
Are carbohydrates hydrophobic or hydrophilic? What are the implications of this with passing through cell membranes?
They're hydrophilic, which means they can't pass through cell membranes without help.
What are three common disaccharides and what sugar units are they made of?
Maltose - two glucose units
Lactose - galactose and glucose
Sucrose - fructose and glucose
What are the two different types of glycosidic bonds?
Alpha and beta glycosidic bonds.
What is the main storage polysaccharide in mammals?
What bonds does glycogen have and what implications does this have on the shape of the molecule?
Alpha 1,4 and alpha 1,6. This means the molecule is highly branched.
What is starch made of?
Polymer of glucose, mixture of amylose (a1,4 bonds) and amylopectin (a1,4 and a1,6 bonds).
Where is starch found?
What is cellulose made of?
Polymer of glucose joined by B1,4 bonds.
What are the three main dietary monosaccharides?
Glucose, fructose and galactose.
Which tissues have an absolute requirement for glucose?
Red blood cells, white blood cells, kidney medulla, lens of the eye.
What are the functions of glycolysis?
To oxidise glucose and produce NADH. To synthesise ATP from ADP. To produce C6 and C3 intermediates.
What is the overall reaction of glycolysis?
Glucose (C6) + 2Pi + 2ADP + 2NAD+ ----> 2 pyruvate (C3) + 2ATP + 2NADH + 2H+ +2H2O
What is the committing step of glycolysis?
Step 3, it commits glucose to metabolism via glycolysis.
What does substrate level phosphorylation refer to in glycolysis?
Reactions 7-10 where Pi is transferred to ADP to make ATP.
What are the three irreversible steps of glycolysis?
1, 3 and 10.
How many ATP molecules are produced per glucose molecule in glycolysis?