3 Biochemical processes in cells 1

Organic ___________ provide a source of energy for living organisms. Chemical ____________ may release energy or require energy. All metabolic reactions in living organisms are _____________ by _____________. Enzymes are ___________ molecules, each with an active _______ and each being ___________ in its action. The ________ of ___________ of an enzyme depends on a number of different factors. 2

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Factors affecting enzyme activity Inhibition and Enzyme concentration 7

Exploring photosynthesis Photosynthesis is the process of converting the energy of _________to chemical energy in sugars. The raw materials of photosynthesis are ________ __________ and water, and the __________ are carbohydrate and __________. In plants and algae, photosynthesis __________ in ______________. The main light-trapping pigments are chlorophylls, located on the _______ membranes in chloroplasts. 8

Light-dependent grana 9

Light-independent (carbon reduction) stroma 10

Carbon reduction in C3 plants Figure 3.22 Simplified version of the Calvin cycle. Although it is a cycle, a starting point is denoted by an asterisk (*). Does the cycle require or release energy? From where does this energy come immediately? n the first place? 11

Carbon reduction in C4 plants 12

Putting photosynthesis together 13

Photosynthesis can be divided into a light- __________ and a light _______________ (carbon reduction) stage. The light-dependent stage occurs on the _________ membranes inside chloroplasts. The light-dependent stage results in the formation of _____ and acceptor molecules loaded with ______. The carbon reduction stage occurs in the _________ of chloroplasts. The process of carbon ____________ involves the Calvin cycle in which carbon dioxide is fixed. 14

In C4 plants, preliminary steps __________ the Calvin cycle. One product of the Calvin cycle is a 3-C compound (_______) which can react to form various sugars, including glucose, fructose and sucrose. Sucrose is the form in which carbohydrates are _____________ through the __________. Starch is the __________ carbohydrate in plant cells. 15

Cellular respiration: energy transfer from glucose to ATP 16

Two types of cellular respiration 17

Cellular respiration is the series of reactions that result in the __________ of chemical ________ of organic compounds, commonly glucose, to the production of _______. ATP is the form of chemical _________ used by cells to supply the energy needed for all ________gonic reactions. Respiration in the __________ of oxygen is termed ___________ respiration. Respiration in the ___________ of oxygen is termed ______________ respiration. 18

Aerobic respiration: making ATP in the presence of oxygen. 3 steps! 19

Energy yield in ATP 20

Figure 3.32 The process of aerobic respiration can be shown in several ways. What is the difference between representations (a) and (b), and between (b) and (c)? 21

Putting photosynthesis and respiration together Figure 3.33 Photosynthesis converts radiant energy to chemical energy in organic molecules such as carbohydrates. The energy in these molecules is released by cellular respiration and ATP is produced. ATP provides energy for all cellular processes. 22

Aerobic respiration can be divided into three stages: ___________, ________ cycle and ___________ transport. Glycolysis is the _________ of glucose to pyruvate. In the Krebs cycle, ___________ is converted to carbon dioxide. During __________ respiration, energy released in some reactions is transferred to ATP. 23

___________ molecules, also called _______ molecules, gather the ____ atoms that are released during steps in aerobic respiration. Electron transport involves the transfer of electrons from ___________ atoms along a series of acceptor molecules. The last electron acceptor is __________ and ________ molecules are produced as a result. The total energy ________ from the aerobic respiration of ____ glucose molecule is ____ molecules of ATP in most cells and ___ ATP in a few. 24

Making ATP without oxygen: anaerobic respiration 25

Anaerobic respiration occurs in the absence of ___________. Anaerobic respiration begins with the breakdown of glucose to _________. The final product(s) in anaerobic respiration depend on the different _________ present in various organisms. In human muscle tissue, pyruvate is converted to ___________ during anaerobic respiration. In yeasts, pyruvate is converted to an _________ (ethanol) and ________ ____________. The ________ yield from anaerobic respiration is ___ molecules of ATP per ___________ of glucose. 26

What happens during starvation? Organic compounds from the digestion of carbohydrates, fats and proteins can enter the cellular respiration pathways at various points. 27