ch 2 cycling through life: metabolism Flashcards
metabolism
metabolism is the term for all the
chemical reactions our body must undergo to sustain life
metabolism
proteins called enzymes control the
rate of these reactions that are of 2 types
* anabolic reactions
* catabolic reactions
metabolism
anabolic reaction
require a source of energy to build up compounds that the body needs
metabolism
catabolic reaction
break down larger molecules into smaller ones, releasing energy
tip: it can be catastrophic when things break down
metabolism
the chemical alteration of molecules in the cell reffered to as
cellular metabolism
metabolism
enzymes are biological catalysts that acclerate
chemical reactions without being changed
metabolism
one way we can control the rate of our cellular metabolism is through the production of
enzymes or lack of production
metabolism
what energy can cells use
adenosine triphosphate (ATP)
metabolism
ATP’s energy is stored in the bonds that attach the
second and third phosphate groups
metabolism
ATP is composed of
3 phosphate groups attached to adenosine
(a nitrogenous base of adenine paired with ribose)
metabolism
when a cell needs energy what is the first step
- removes one or two phosphate groups
- releasing energy and converting ATP into either the
two-phosphate molecule adenine diphosphate (ADP) or the one-phosphate molecule adenosine monophosphate (AMP)
metabolism
when a cell needs energy what is the second step
later through additional metabolic reactions the second and third phosphate groups are reattached to adenosine reforming an ATP molecule until energy is needed again
ATP works like a rechargeable battery
metabolism
most often we cycle through
ADP and ATP
AMP is only used in special scenarios
energy from food
ATP is created via
cellular respiration
a process that occurs in and around the mitochondria of a cell
energy from food
cellular respiration is a series of reactions that includes
- glycolysis
- the Krebs cycle
- electron transport cycle
energy from food
cellular respiration starts with a
single molecule of glucose and produces 38 molecules of ATP
this process requires energy sources of its own which we gain from the foods we eat
energy from food
the most efficient source (glucose) is gained from
- carbohydrate metabolism
- when this is used up we turn to the products of lipid metabolism
- finally to the products protein metabolism
energy from food
each energy source enters the cellular respiration process at
different points
carbohydrate metabolism
the metabolism of all carbohydrates leads to the eventual production of
glucose
carbohydrate metabolism
the glucose is then utilized in the first phase of cellular respiration
glycolysis
lipid metabolism
lipids contain about 99% of the body’s stored
energy and can be digested at mealtime
lipid metabolism
where are lipids stored in the body
instead of fats going straight to the hips it is more inclined to be stored in adipose tissue (generally identified as body fat)
lipid metabolism
when the body is ready to metabiliza lipids an enzyme called
lipase splits them into their monomer units:
* glycerol
* fatty acid chains
lipid metabolism
glycerol
- has 3 carbons
- then converted into pyruvate
lipid metabolism
acetyl CoA
- a different series of reactions of catabolic reactions breaks apart 2 carbon atoms from the end of a fatty acid chain to form this
- then enters the Krebs Cycle to produce ATP
- those reactions to continue to strip 2 carbon atoms at a time until the entire fatty acid chain is converted into acetyl CoA molecules
protein metabolism
protein metabolism focuses on producing the
amino acids needed for synthesis of protein molecules within the body
protein metabolism
but like the lipids the amino acids can be converted into
- pyruvate
- acetyl CoA
protein metabolism
additionally protein metabolism generates energy molecules such as
- NADH and FADH2
- that power the final step of cellular respiration–the electron transport chain
