Bio 1406 Exam 3 Collin College

Photosynthesis equation

6CO2 + 6H2O --> light energy --> C6H12O6 + 6O2

Cellular respiration equation

C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP

Location of Photosynthesis

Chloroplast

Location of Cellular respiration

Mitochondria

Why it is accurate to say that life on Earth is solar powered?

Animals, including humans, need plants for food and the oxygen they produce. Sunlight is needed in order to undergo photosynthesis.

How are breathing and cellular respiration related?

Breathing supplies the oxygen needed to produce ATP, the energy currency of the body. Breathing is necessary for cellular respiration because it helps to maintain the main metabolic process of the body.

Efficiency of Cellular Respiration

38%

Efficiency of burning gasoline in auto engine

25%

How does the human body uses its daily supply of ATP?

ATP (energy) is consumed by various activities in kcal.

Kilocalorie

A unit of energy equal to 1,000 calories.

How is the energy in a glucose molecule released during cellular respiration?

The energy is broken down through glycolysis, oxidation of pyruvate, citric acid cycle, and oxidative phosphorylation. Exergonic; -686 kcal.

How are redox reactions used in cellular respiration?

Both oxidation and reduction occur. The loss of electrons is oxidation, so addition of electrons is reduction this is used in cellular respiration when glucose is losing hydrogen atoms and oxygen is gaining hydrogen atoms

Describe the general roles of dehydrogenase, NADH, and the electron transport chain in cellular respiration.

NAD+ reduces to NADH- dehydrogenase strips two hydrogen atoms from molecule (NADH)NADH- helps get the ATP out of the chain, sends two electrons to the transport chainElectron transport- "electron carries" carries electrons down the train into ATP where it is released

Compare the reactants, products, and energy yield of the stages of cellular respiration

Glycolysis) breaks down glucose, into two molecules of a three-carbon compounds called pyruvates

Oxidation of Pyruvate) the conversion of pyruvate to acetyl CoA (2 carbon compounds) 2 CO2s are released

Citric Acid Cycle) breakdown of 2 acetyl CoA into 4 CO2 (containing one carbon each)

Oxidative Phosphorylation) the electron transport and the chemiosmosis (converts NAD+ to NADH and FAD to FADH2)

Region where glycolysis occurs

Cytosol

Region where oxidation of pyruvate occurs

Mitochondrial matrix (Oxidation of pyruvate)

Region where citric acid cycle occurs

Mitochondrial matrix (Citric Acid Cycle)

Region where oxidative phosphorylation occurs

Mitochondria's inner membrane

Does glycolysis have substrate-level and chemisosmosis ATP production?

Yes, ATP is produced at both the substrate level and oxidative phosphorylation level. (Glycolysis)

Does oxidation of pyruvate have substrate-level and chemiosmosis ATP production?

No, ATP is not substrate-level produced. However, it is produced through oxidative phosphorylation.

Does the Citric Acid Cycle have substrate-level and chemiosmosis ATP production?

Yes, ATP is produced at both the substrate level and oxidative phosphorylation level. (Citric Acid Cycle)

What is the gross total ATP produced in Cellular respiration?

38 total

Why is the gross total ATP produced not what is accurately depicted?

Because 2 ATP are used while shoving into the mitochondria.

What is the net ATP produced in Cellular Respiration?

34(OP) + 4 (SL) = 38 (Gross total) - 2 (shoved) = 36 (net)

Fermentation

anaerobic process; ATP-producing Catabolic pathway

Compare the reactants, products, and energy yield of alcohol and lactic acid fermentation

lactic acid fermentation- occurs in your muscles where NADH is oxidized to NAD+ and pyruvate is reduced to lactate.

alcohol fermentation- occurs in brewing, wine making, and baking and produces C02 and ethanol (c02 is actually the bubbles in wine/beer, releases yeast)

Distinguish between obligate anaerobes and facultative anaerobes

Obligate or strict anaerobes can't tolerate oxygen and must be cultured under conditions where oxygen is absent. Facultative anaerobes can grow in the presence of oxygen or without oxygen.

Explain how carbohydrates, fats, and proteins are used as fuel for cellular respiration.

carbohydrates- glucose to pyruvate to ATP

fats- make cellular fuel because they contain hydrogen atoms (energy rich electrons) also make twice as much ATP than carbohydrates/ proteins

proteins- amino acids to pyruvate to ATP

Explain why a gram of fat yields more ATP than a gram of starch or protein.

Fats yield more ATP because they contain more energy-rich electrons inside its plentiful hydrogen atoms.

Explain how nutrients are used in biosynthesis.

Biosynthesis is the production of organic molecules using energy requiring metabolic pathways. Not all food molecules are used to make ATP; others are used as raw materials to help build up certain structures in the cell.

Define autotroph

Organisms that make their own food

Define heterotroph

Organisms that obtain food by consuming other living things

Define producers

Organisms that produce their own food

Define photoautotroph

capable of synthesizing their own food from inorganic substances using light as an energy source and carbon dioxide as a carbon source

Structure of chloroplast

organelle for photosynthesis

has double membrane

contains discs called thylakoids

thylakoids contain chlorophyll

stack of thylakoids called granum

thylakoids surrounded by a fluid called stroma

Where is light energy converted to chemical energy?

The chlorplast

How plants produce oxygen

by splitting water

Describe the experiments that revealed the source of the oxygen produced during photosynthesis.

This was discovered when H₂O with a heavy isotope of oxygen was tracked and found in oxygen and not other products.

Describe the role of redox reactions in photosynthesis and cellular respiration

Photosynthesis:

-6CO₂ is reduced to C₆H₁₂O₆

-6H₂O is oxidized to 6O₂

Cellular respiration:

-C₆H₁₂O₆ is oxidized to 6CO₂

-6O₂ is reduces to 6H₂O

Compare the reactants and products of the light reactions and the Calvin cycle. Explain how photosynthesis relates to these reactions.

Light reactions

-reactants=H₂O and light

-products=electrons (NADPH), ATP, and O₂

Calvin Cycle

-reactants=CO₂, NADPH, and ATP

-products=Sugar, ADP and a third phosphate

group, and NADP

Describe the properties and functions of the different photosynthetic pigments.

Xanthophylls - yellow

Carotenes- Orange

(both can't absorb yellow, orange, or red well)

Chlorophyll a- blue-green (can't absorb blue-green well)

Chlorophyll b- yellow-green (can't absorb yellow-green well)

Explain how photosystems capture solar energy.

Pigments found in the stroma attract protons and absorb them. They pass the energy from molecule to molecule until it reaches the reaction center. The reaction center contains chlorophyll a moleculesand a molecule called the primary electron receptor, which is capable of accepting electrons and becoming reduced. The solar-powered transfer of an electron from the reaction center chlorophyll a to the primary electron acceptor is the first step of the light reactions.

Explain how the electron transport chain and chemi-osmosis generate ATP, NADPH, and oxygen in the light reactions.

Water is split and provides O₂ as a product as well as an electron for the photosystem which is then excited. When an excited electron falls down the chain, it releases energy that aids in the synthesis of ATP by chemiosmosis (the active transfer of H⁺ through a permeable membrane). After photosystem II, the excited e⁻ from that process is passed through a short electron transport chain to NADP⁺ changing it to NADPH.

Relate the structures within the thylakoid membrane to the steps of photophosphorylation.

the thykaloid membrane includes numerous copies of the 2 photosystems and the electron transport chain.

Describe the reactants and products of the Calvin cycle. Explain why this cycle is dependent upon the light reactions.

The Calvin Cycle happens in the Stroma and uses NADPH, ATP, and Carbon Dioxide and produces NADP+, ADP +P. and high energy sugars.

Compare the mechanisms that C3, C4, and CAM plants use to obtain and use carbon dioxide.

-C3 (trees, rice, wheat, and soy beans) and C4 plants (grasses, corn, and sugar cane) have their stomata open during the day and go through the calvin cycle-CAM plants (pineapple, cacti, and succulents) have theirs open during nighttime.

Review the overall process of the light reactions and the Calvin cycle, noting the reactants, products, and locations of every major step

The Calvin cycle takes place in the stromatolites of chloroplasts. It assembles sugar molecules using CO2 (from the air), ATP & NADPH (from the light reactions). CO2 is incorporated into organic compounds in carbon fixation. The carbon compounds are then reduced to sugars. G3p is produced which is an energy rich, 3 carbon sugar used to make glucose, sucrose, & other organic molecules.

Explain how rising carbon dioxide levels may affect plants. Describe the greenhouse effect.

greenhouse effect: caused by greenhouse gases in our atmosphere trapping and redirecting heat back to Earth, increasing temperatures

global climate change-increased carbon dioxide levels increase plant productivity

Explain how fossil fuel consumption and deforestation affect climate change.

Burning of fossil fuels have caused melting of polar ice, rising sea levels, extreme weather patterns, droughts, increased extinction rates, the spread of tropical disease. When trees are cut down there are less plants to absorb carbon dioxide for photosynthesis.

Define biochemical pathway

In biology, the long chains of chemical reactions that take place in the normal operation of living systems.

aerboic reaction

the process of cellular respiration that takes place in the presence of oxygen gas to produce energy from food

anaerobic reaction

a chemical process in which energy is produced from food without using oxygen, for example, by yeast

Define chemiosmosis

the movement of ions across a semipermeable membrane, down their electrochemical gradient

Define ATP synthase

a special protein that allows the hydrogen ions back into the matrix, and on the way in, energy is used to phosphorylate an ADP to an ATP

Define redox reaction

Short for oxidation-reduction; a chemical reaction in which electrons are lost from one substance (oxidation) and added to another (reduction). Oxidation and reduction always occur together.

Define calorie

the energy needed to raise the temperature of 1 gram of water through 1 °C

Photophosphorylation

The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.

Where in the cell does chemiosmosis occur?

mitochondria

compare chemiosmosis in chloroplast with mitochondria

In mitochondria, the high-energy electrons are extracted from the food molecule (from redox reaction) whereas in chloroplast the source is from the photons captured from the light source.

How much ATP does FADH2 create

2 ATP

How much ATP does NADH create

3 ATP