EnergyChapter 4

Overview

Energy = Capacity to do Work

Kinetic = Energy of Moving Objects

Potential = Stored Energy

Energy can not be created or destroyed Energy can change forms – heat, light,

chemical, matter

Laws of Thermodynamics

A) a ball rolling down a hillB) flowing water turning a turbineC) a chameleon tongue catching a bugD) a covalent bond linking phosphate

moleculesE) a pitcher throwing a baseball

Which of the following is NOT a form of kinetic energy?

A) be transferred and transformed; created or destroyed

B) be produced and generated; moved or relocated

C) hustle; flowD) be increased and decreased; eliminatedE) cycle; flow

The first law of thermodynamics states that energy is constant; it can _________, but not __________.

Overview

In living systems: ATP = energy

ATP = Rechargeable Battery

Question:

Uses about 1% or less of energy from sun◦ 30% is reflected back into space or◦ 70% absorbed by Earth and converted to heat

energy

Photosynthesis

Photosynthesis process

1. Photo reaction Sunlight + water = energy + Oxygen

2. Synthesis reaction Carbon dioxide + energy = sugar

Location of Photosynthesis

Location of Photosynthesis

A) water.B) sunlight.C) sugar molecules. D) oxygen.E) carbohydrate molecules.

Energy supporting most of the life on this planet originally came from:

Plants have pigments that can absorb light of certain wavelengths

How is Light Energy Captured?

Light is a form of kinetic energy that is packets of energy called photons moving in a wave Different sizes of wave produce the different

parts of electromagnetic spectrum Our eyes can see 740 (red) - 400 (blue) nm Plant pigments absorb light in different

wavelengths like our eyes◦ Chlorophyll a and b = absorb red/orange and

blue/violet◦ Thus they reflect green light, which is why plants are

green

Light Energy

There are other plant pigments in smaller amounts.

In the fall, the chlorophylls break down first, leaving other pigments that reflect more orange and red light.

A) the violet-blue portion.B) the yellow-green portion.C) the red-orange portion.D) Both a) and b) are correct.E) Both a) and c) are correct.

The most effective portion(s) of the visible spectrum in driving photosynthesis is (are):

Built up potential energy

When released = kinetic energy

which can be used to form ATP

A) in the stroma of the chloroplastB) in the thylakoid membraneC) in the Hobbesian membraneD) in the cellular cytoplasmE) around the chlorophyll molecule

Where does the Calvin cycle take place?

Where does the plant biomass come from?

A) glucoseB) OxygenC) SugarsD) carbon dioxideE) None of the above; all are products

of photosynthesis.

Which of the following is NOT a product of photosynthesis?

A) Pigments absorb light energy, which excites electrons.

B) The energy of the sun is captured as potential energy.

C) Water molecules split, providing a source of electrons.

D) Only a) and c) are correct.

E) a), b), and c) are all correct.

Which of the following statements about the light reactions of photosynthesis is correct?

A) oxygen and carbon dioxide diffuse out of vacuoles when vacuole pressure is reduced.

B) thylakoids become depressurized and release nitrogen gas.

C) oxygen is a by-product of photosynthesis.

D) the cell wall is permeable to the gases released by the stomata.

E) due to anaerobic conditions underwater, the plant must resort to fermentation, causing the production of excess carbon dioxide.

Bubbles come from the leaves of an Elodea plant when it is put under water because:

A) to replace electrons that are excited by light energy and passed from molecule to molecule down an electron transport chain.

B) to serve as a high-energy electron carrier.

C) to concentrate the beams of light hitting a leaf, focusing them on the reaction center.

D) to provide the protons necessary to produce chlorophyll.

E) to replenish oxygen molecules that are lost during photosynthesis.

Photosynthesizing plants rely on water:

A) rubisco.B) ribulose biphosphate.C) ATP-synthase.D) glyceraldehyde-3-phosphate.E) crassulacean acid.

The most abundant protein in the world is the enzyme that initiates the fixation of carbon in the Calvin cycle. This enzyme is called:

Openings in leaves for gas exchange – what gases?

Pleural form = stomata

A) stroma.B) stomata.C) grana.D) thylakoid.E) roots.

The carbon dioxide needed for photosynthesis enters the plant through the:

Leaves have evolved to maximize photosynthesis while minimizing water loss◦ Broad surface oriented

toward sunlight◦ Small stomata

regulating air intake and transpiration

Shape of leaf and Photosynthesis

Which is why plants from different ecosystem communities can have very different leaves

◦ Plants compete for sunlight, so some leaf modifications help a plant climb to sunlight

Large leaves of tropical forest floor plants

◦ Collect as much light as possible

Low light conditions

Pine trees can photosynthesize in winter due to compounds in sap that act as antifreeze.

Pine trees can lose up to 26 gallons of water on a sunny, hot day. Under dry conditions, they lose less water than other types of trees

1) pine needle has small surface area, 2) leaves (needles) have a waxy cuticle layer and 3) stomata are recessed into the needle surface, so

somewhat protected from the wind so less evaporation.

Examine the structure of a typical leaf and briefly describe how each of the following features contributes to the leaf’s function.

1. Interior air spaces

2. Various shapes and sizes, but always relatively thin

3. Stomata

4. Veins

All organisms need a form of energy ◦ Cell metabolism◦ Muscle action◦ Eliminating waste◦ Reproduction◦ Growth of tissues, development◦ Behavior

Not all use oxygen, but eukaryotes do

Cell Respiration

Overview of Process

A) oxygen is produced during metabolic activity.B) light energy is converted into kinetic energy.C) oxygen is used to transport chemical energy

throughout the body.D) energy from the chemical bonds of food

molecules is captured by an organism.E) ATP molecules are converted into water and

sugar.

Cellular respiration is the process by which:

Glyco = sugarLysis = splitting

Aerobic Respiration 1. Krebs Cycle 2. Electron transport phosphorylation or chain

Electron Transport Chain=

Oxygen used to accept H+ plus electrons to form water & large amounts of ATP

32 ATP from 1 sugar molecule!

Total: 2 from glycolysis, 2 from Krebs Cycle + 32 from ETC = 36 ATP net gain

Why is this cell respiration? Oxygen + glucose =

Carbon dioxide + water + 36 ATP Why we breathe

◦ Oxygen is carried to blood the transported to all cells

◦ Waste product, carbon dioxide, diffuses to blood and transported to lungs for release

Interesting note: Water produced = metabolic water. Some grain beetles live in dry grain & can exist without ever drinking – live on metabolic water only.

Animation Review

A) is not performed in plants, which get their energy solely through photosynthesis.

B) occurs in all cells.C) is performed solely on the glucose

ingested by the organism.D) is also referred to as the Krebs cycle.E) completely oxidizes glucose to carbon

dioxide.

Glycolysis:

A) lactic acid; O2; acetaldehyde

B) pyruvate; ATP; NADHC) acetyl-CoA; ADP; Pi

D) galactose; H2O; ATP

E) sucrose; lactic acid; FADH

In glycolysis, one molecule of glucose containing six carbons is converted to two molecules of ______ containing three carbons each. This reaction also yields two molecules of _____ and two molecules of _____.

A) the products of glycolysis are further broken down, generating additional ATP and the high-energy electron carrier NADH.

B) cellular respiration can continue even in the absence of oxygen.

C) the products of glycolysis are completely converted into ATP.

D) high-energy electron carriers pass their energy to molecules of sugar which store them as potential energy.

E) the products of glycolysis are further broken down, generating additional ATP and the high-energy electron carrier NADPH.

During the Krebs cycle:

A) extreme sensitivity to UV light, resulting in skin cancer at a very young age

B) fragile bones and arthritis

C) extreme muscle weakness

D) color blindness

E) inability to absorb iron, resulting in extreme anemia

An inherited disease results from abnormal mitochondria passed from mother to child. Using your knowledge of the function of mitochondria within human cells, which of the following is the most likely description of the symptoms of this disease?

Alternatives

Hydrothermal vents•First discovered by explorers of the ocean floor

in the 1970’s•Surprise discovery: vents support large community of animals• Too deep for photosynthesis• What food supports animals there?• Turns out- bacteria capable of digesting and

getting energy from the sulfides released by the vents

A) Fermentation is a less efficient energy producer than aerobic respiration.

B) Fermentation utilizes the electrons generated in the glycolytic breakdown of glucose.

C) Fermentation is an anaerobic process.

D) In fermentation, the molecules that are used as final electron acceptors differ from those used when glycolysis occurs in the presence of oxygen.

E) All of the above are correct.

Which of the following statements about fermentation is NOT correct?

Why is energy stored in sugar molecules rather than in ATP?

Why is long term storage in the form of lipids and not sugars?

Questions:

The human red blood cell does not have any mitochondria. Why do you

think that might be? Hint: What does a red blood cell

carry?

Read chapter 5 on DNA