Metabolism Lab Part 1: cellular respiration Aerobic respiration: C6H12O6 + __  CO2 + H2O + Energy Anaerobic respiration: C6H12O6  nitrates/sulfates + CO2 + Energy (e.g., “_____ gas”) Fermentation Yeast: C6H12O6  _______ + Energy Animals under oxygen deficit: C6H12O6  ______ acid + Energy Lactic acid is broken down when __ is available All 3 process use glycolysis, which is anaerobic But products differ

Respirometer C6H12O6 + O2  CO2 + H2O + Energy Which gas(es) go in? mealworm Which gas(es) come out?

Add soda lime to _______ CO2 Now gas movement is primarily inward mealworm

Movement of meniscus reflects oxygen consumption mealworm

Measuring oxygen consumption 1 ml pipette 0.1 ml

Respiration procedures Tare scale Follow instructions on pgs 52-55 Pose hypotheses before conducting tests; pg 63

Ending measurement of one trail is the beginning From pg 59: Ending measurement of one trail is the beginning measurement of the next trial 0.35 0.33 0.37 0.35

Expected values for calculated metabolic rate (G): 10.00 –> 130.00 If your calculated values are outside this range you’ve probably miscalculated. The point of questions 12-17 is to compare your daily (24 hr) caloric intake to that of a single pea or worm.

“warm blooded” versus “cold blooded” Terms are misleading Snakes are cold blooded, right? What if the snake has been basking on a hot rock? Two issues here: Whether heat is generated from within the body Whether blood temperature changes with outside temperature

Better terms: Endotherm: body heat generated ______ E.g., mammals: requires ~70% of food energy Ectotherm: body heat absorbed from _______ E.g., reptiles: require 10x less food energy Homeotherm: keep internal body temp. _______ E.g., mammals Poikilotherm: internal temp. ______ with outside E.g., most fish

Pound for pound, smaller animals need ____ energy Elephant 0.1 kg elephant tissue Mouse 0.1 kg mouse tissue

Some vocabulary terms for experimental science Dependent variable: the variable that is expected to change as other factors are adjusted. Independent variable: variable(s) that is/are not influenced by experimental treatments. Experimental treatment: the factor whose influence is being tested. Usually administered at a range of levels. Experimental control: an experimental setup in which the treatment or condition is not applied. Used to confirm that outside factors do not influence results of the experiment.

Part 2: Photosynthesis Light Energy + H2O + CO2  C6H12O6 + O2 Essentially the opposite of cellular respiration: C6H12O6 + O2  CO2 + H2O + Energy How might we experimentally increase photosynthesis? Prepare test tubes as described on page 56