BIOL 230:SA #9

In which of the following molecules is sunlight energy FINALLY stored during photosynthesis? a. Glucose b. NADPH c. ATP d. Both Glucose and NADPH e. Both NADPH and ATP

a. Glucose

Three batches of radish seeds - each 1.5 grams - were weighed out. The following experimental treatments were done: A. Seeds not moistened (left DRY) placed in LIGHT B. Seeds placed on moistened paper towels in LIGHT C. Seeds placed on moistened paper towels in DARK After 1 week, all plant material was dried in an oven overnight (no water was left) and the plants dry biomass was measured in grams on a scale. Note: Dry biomass is the weight of all the molecules in a living thing after water is removed through drying. In which of the experimental conditions above is CELLULAR RESPIRATION happening (which would result in a LOSS of MASS)? a. In A, B, and C b. Only in B c. Only in C d. In both A and B e. In both B and C

a. In A, B, and C Always remember that ALL LIVING THINGS are doing CELLULAR RESPIRATION to be alive!Plants are living things, and so plants have to do cellular respiration - all the time, both day and night, in light and in dark - to be alive! Like in this big idea...Key Idea (Gorilla!) #4: All living things - plants, animals, bacteria, fungi - do cellular respiration to transfer energy from food to ATP, and in the process release mass in the form of carbon dioxide.In addition, seeds have living cells in them that can undergo mitosis (remember!) to build a whole plant. These living cells in the seeds have to be doing cellular respiration, even if only a little bit because they are so small and not doing much.Finally, remember that cellular respiration releases carbon dioxide, which results in LOSS of MASS.

Which of the following are ordered correctly from the LARGEST to the SMALLEST? a. plant cell, chloroplast, chlorophyll, glucose, carbon dioxide b. chloroplast, plant cell, glucose, carbon dioxide, chlorophyll c. plant cell, chlorophyll, chloroplast, glucose, carbon dioxide d. plant cell, glucose, chloroplast, carbon dioxide, chlorophyll e. plant cell, glucose, chloroplast, chlorophyll, carbon dioxide

a. plant cell, chloroplast, chlorophyll, glucose, carbon dioxide Please remember not to memorize! Rather, ask yourself what is the structure of this? What is is made of? From LARGEST THINGS in the list... Is the object a cell? (e.g. plant cell, bacterial cell, yeast cell, human body cell, amoeba) Is it a membrane-bound organelle inside a cell? (e.g. mitochondrion, chloroplast) Is it a collection of molecules inside a cell? (e.g. virus, ribosome) Is it a single big molecule? (e.g. chlorophyll, prion, hemoglobin, DNA, which all have thousands of atoms) Is it a single small molecule? (e.g. glucose/sugar is 24 atoms, carbon dioxide is 3 atoms, water is 3 atoms) ...to SMALLEST THINGS in the list.

A mature tree can have a DRY MASS of 1 ton or more (after removing all the water), yet it starts from a seed that weighs less than 1 gram. Which of the following contributes ANY MASS to the DRY MASS of the grown tree? a. Only sunlight b. Both minerals and water c. Only water d. Only minerals e. Minerals, water, and sunlight

b. Both minerals and water Most of the dry biomass of a tree comes directly from the mass of glucose (C6H12O6) that it synthesizes through photosynthesis. So, the tree gets some of its mass from the mass of Carbon atoms (C), some from the mass of Hydrogen atoms (H), and some from the mass of Oxygen atoms (O). Could you explain to a colleague where each of these atoms came from before they were synthesized into glucose?!? A little bit of the mass of the tree is directly from minerals it takes up from the soil. But sunlight has no mass and does not directly contribute any mass to the tree itself, even though energy from sunlight is stored in the bonds of the sugar molecules made during photosynthesis.

Three batches of radish seeds - each 1.5 grams - were weighed out. The following experimental treatments were done: A. Seeds not moistened (left DRY) placed in LIGHT B. Seeds placed on moistened paper towels in LIGHT C. Seeds placed on moistened paper towels in DARK After 1 week, all plant material was dried in an oven overnight (no water was left) and the plants dry biomass was measured in grams on a scale. Note: Dry biomass is the weight of all the molecules in a living thing after water is removed through drying. In which of the experimental conditions above is PHOTOSYNTHESIS happening (which would result in a GAIN of MASS)? a. In A, B, and C b. Only in B c. Only in C d. In both A and B e. In both B and C

b. Only in B Always remember to check for two key requirements for photosynthesis:Is there LIGHT present?Are there CHLOROPHYLL molecules in CHLOROPLASTS (organelles) in LEAVES with access to light?If there is no light in the experimental condition, there is no photosynthesis...period. While seeds have the potential to photosynthesize, they cannot do so until at least a little leaf is built and has access to sunlight energy. Finally, remember that photosynthesis brings in carbon dioxide and water to make sugar, which results in a GAIN of MASS.

Three batches of radish seeds - each 1.5 grams - were weighed out. The following experimental treatments were done: A. Seeds not moistened (left DRY) placed in LIGHT B. Seeds placed on moistened paper towels in LIGHT C. Seeds placed on moistened paper towels in DARK After 1 week, all plant material was dried in an oven overnight (no water was left) and the plants dry biomass was measured in grams on a scale. Note: Dry biomass is the weight of all the molecules in a living thing after water is removed through drying. What will the relative weight of the dry mass in each dish be at the end of the experiment, and why? a. A=B=C, because mass is conserved so they will all still weigh the same b. B>C>A, because B and C are both photosynthesizing and gaining mass c. B>C>A, because A is NOT doing either photosynthesis (gaining mass) or cellular respiration (losing mass) d. B>A>C, because C is only doing cellular respiration and losing mass e. B>A>C, because A and B are both doing photosynthesis and gaining mass

d. B>A>C, because C is only doing cellular respiration and losing mass Condition B: LOTS of photosynthesis and LOTS of cellular respiration; weighs the most, is growing, and is building more mass than its losingCondition C: NO photosynthesis and LOTS of cellular respiration; weighs the least, is losing weight, and on its way to dyingCondition A: NO photosynthesis and only a LITTLE cellular respiration; close to its starting weight, and losing just a little weightIt's helpful to think about these two questions when you encounter transformation of energy and matter problems in biology...Where is PHOTOSYNTHESIS happening (GAIN of MASS)?

Which of the following statements is most scientifically accurate? a. Plants use carbon dioxide to do cellular respiration, while humans and animals use oxygen. b. Plants use the process of photosynthesis to transform energy from food, but animals use cellular respiration. c. Plants photosynthesize in the light and do cellular respiration only at night. d. Plants photosynthesize in the light and do cellular respiration all the time. e. The purpose of plant photosynthesis is the same as the purpose of animal cellular respiration.

d. Plants photosynthesize in the light and do cellular respiration all the time. First, plants are living things, and so plants have to do cellular respiration - all the time, both day and night - to be alive! Plants do cellular respiration in their mitochondria just like other eukaryotes (like YOU because YOU are a EUKARYOTE, too). Just like you, plants use oxygen to transfer the energy in food (sugars) into ATP, which is just a more usable form of energy in cells. Like in this big idea...Key Idea (Gorilla!) #4: All living things - plants, animals, bacteria, fungi - do cellular respiration to transfer energy from food to ATP, and in the process release mass in the form of carbon dioxide.In addition, plants also have the amazing ability to do photosynthesis, which is to build sugars out of carbon dioxide and water, and store sunlight energy in those sugars. This happens in a different part of a plant cell in the chloroplasts. Just like in this big idea...Key Idea (Gorilla!) #2: The purpose of PHOTOSYNTHESIS is to capture sunlight energy and store it as chemical energy in the bonds of sugars built from carbon dioxide molecules from the air, making food for all living things.Finally, remember that chloroplasts and mitochondria are organized bags (organelles) within a bigger eukaryotic cell. Evidence suggests that both chloroplasts and mitochondria used to be free-living organisms similar in size and structure to bacteria. We studied that during the first part of the course - endosymbiotic theory and Lynn Margulis, remember!

In which of the following molecules is sunlight energy INITIALLY stored during photosynthesis? a. Glucose b. NADPH c. ATP d. Both Glucose and NADPH e. Both NADPH and ATP

e. Both NADPH and ATP Sunlight energy is INITIALLY stored in two small "energy carrier" molecules called NADPH and ATP during the LIGHT REACTIONS. Then, in a second process, these energy carriers will later contribute energy to the building of GLUCOSE/SUGAR (C6H12O6) during the CALVIN CYCLE, which is where sunlight energy is FINALLY stored at the end of photosynthesis.

What happens to the OXYGEN GAS that you INHALE? a. It becomes part of carbon dioxide molecules. b. It becomes part of water molecules. c. It is exhaled unchanged. d. It either becomes part of carbon dioxide molecules or part of water molecules. e. It either becomes part of water molecules or is exhaled unchanged.

e. It either becomes part of water molecules or is exhaled unchanged. A very common MISCONCEPTION is that the oxygen gas we breath in - (take a big deep breath right now!) - turns into the carbon dioxide we exhale - (give out a big exhale right now!). You can see why lots of people might think this, but not Team Bio 230 colleagues! We know that there are a LOT of biochemical reactions and steps happening in LIVING CELLS that are invisible to us when we are just thinking about breathing at the level of a human. So, oxygen gas does NOT become part of carbon dioxide molecules.Also, if you have heard of CPR - cardiopulmonary resuscitation - then you likely know that we EXHALE LOTS OF OXYGEN gas unchanged every time we breathe. That is why during CPR medical professionals are breathing into another human who cannot breathe on their own, to get OXYGEN to their cells.Finally, in the process of CELLULAR RESPIRATION - which is happening in most LIVING CELLS in you right now - oxygen gas is important in the final step. Oxygen gas is transformed into WATER at the end of cellular respiration as ATP is made and there are electrons and hydrogen atoms released that combine with oxygen gas to make WATER at the end of cellular respiration.

Where does the OXYGEN GAS that plants release during photosynthesis come from? a. Nutrients b. Carbohydrates c. Sunlight d. Carbon Dioxide e. Water

e. Water