ch 8 - LIPIDS, PROTEIN METABOLISM cellular respiration, energy metabolism

fats

• what they are synthesized by

• what they can be oxidized into

• synthesized by adipocytes, hepatocytes from carbohydrates

• oxidized to generate energy, make new lipid mlcs

lipolysis

• what it is

• where it occurs

• what is broken down into what

process of getting energy from fats

• occurs in cytoplasm of adipocytes

• fats broken into → glycerol, fatty acids

describe what products do after lipolysis

(lipid metabolism) after fats are broken down into → glycerol, fatty acids

• released into bloodstream for tissues to take

• fatty acids converted into acetyl CoA → acetyl CoA enters Krebbs cycle in cellular respiration for ATP generation

which yields the most energy per mass:

• carbs - glucose

• lipids - triglycerides

• proteins - amino acids

triglycerides - yields twice the amt of energy per mass

ketogenesis

• what occurs, and when it occurs

• where it occurs

occurs in the liverwhen excess acetyl co-a builds up

• liver converts excess acetyl co-a into ketone bodies

2 types of ketone bodies & what they are used for

• beta-hydroxybutyrate

• acetoacetate

serve as a source of fuel if glucose levels are low

lipogenesis

• when and where it occurs

• what occurs

  • does it require ATP?

occurs in cytoplasm of adipocytes when glucose levels are high

• converts excess acetyl co-a into fatty acids, which are then packaged as triglycerides (fat energy storage for carbs!)

recap: describe differences btwn lipolysis, ketogenesis, and lipogenesis

lipolysis: getting energy from fats (fats → glycerol and fatty acids → acetyl coA)

ketogenesis: excess acetyl coA (acetyl coA → ketone bodies)

lipogenesis: high glucose levels, excess acetyl coA put into storage (acetyl coA → fatty acids, triglycerides)

if amino acids/proteins are in excess, the body converts them into _____

[glucose or ketone bodies]

gluconeogenesis

• process

• products it creates

breaking down amino acids into hydrocarbons that make glucose

• main product: hydrocarbons

• byproducts: ammonium (NH4+)

list the 3 metabolic states of the body

1. absorptive state

2. post-absorptive state

3. starvation

absorptive state

• when it occurs

• what occurs, how long state can last

• where nutrients go

• occurs after a meal

• body digests and absorbs nutrients (up to 4 hrs)

• nutrients immediately used if energy is used after eating

  • if not, excess is stored in tissues

post-absorptive state / fasting state

• what occurs

• when it occurs

• what occurs as glucose levels begin to drop?

fasting state - food has already been digested, absorbed, and stored

• occurs overnight / when meals are skipped

• as glucose levels drop, pancreas releases glucagon, instructing liver to break down glycogen (stored sugar)

starvation

• when it occurs

• first and second priorities

• process of supplying glucose within the body

occurs when body is deprived of nourishment for extended time periods

• 1st priority: glucose for brain, 2nd: conserving amino acids for proteins

• process

  • fatty acids and ketone bodies used as energy source

  • mlcs converted to acetyl co-a or converted to glucose in the liver

  • carbohydrates → lipids → proteins from muscle broken into glucose