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Prentice Hall midterm


organisms such as plants, which make their own food from sunlight or chemicals


organisms, such as animals, that obtain energy from the foods they consume

Where do plants get the energy they need to produce food?

Plants and some other types of organisms are able to use light energy from the sun to produce food.

What is the role of ATP (adenosine triphosphate) in cellular activities?

ATP is used by all types of cells as their basic energy source.


process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

What did the experiments of van Helmont, Priestly, and Ingenhousz reveal about how plants grow?

In the presence of light, plants transform carbon dioxide and water into carbohydrates, and they also release oxygen.

What is the overall equation for photosynthesis?

carbon dioxide + water —> sugars + oxygen

What is the role of light and chlorophyll in photosynthesis?

Light is a form of energy and chlorophyll absorbs light and the energy from the light.


principal pigment of plants and other photosynthetic organisms; captures light energy

Plants gather the sun's energy with light-absorbing molecules are called...


What happens in the light-dependent reactions?

... use energy from sunlight to produce ATP, NADPH, and oxygen. It takes place within the thylakoid membranes of chloroplasts.

What is the Calvin cycle?

... uses ATP and NADPH from the light-dependent reations to produce high-energy sugars. It takes place in the stroma of chloroplasts and does NOT require light.


saclike photosynthetic membranes found in chloroplasts

Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters known as...



the region outside the thylakoid membranes in chloroplasts


(nicotinamide adenine dinucleotide phosphate) one of the carrier molecules that transfers high-energy electrons from chlorophyll to other molecules.

light-dependent reactions

reactions of photosynthesis that use energy from light to produce ATP and NADPH

ATP synthase

large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

Which are autotrophs?

plants, mushrooms

One of the principal chemical compounds that living things use to store energy is...


Which scientist concluded that most of a growing plant's mass comes from water?

van Helmont

In addition to light and chlorophyll, photosynthesis requires...

water and carbon dioxide

The leaves of a plant appear green because chlorophyll...

reflects green light

The products of photosynthesis are...

sugars and oxygen

The first process in the light-dependent reactions of photosynthesis is...

ATP formation

Which substances from the light-dependent reactions of photosynthesis is a source of energy for the Calvin cycle?


The light dependent reactions of photosynthesis are also known as the...

Calvin cycle

How do heterotrophs and autotrophs differ in the way they obtain energy?

heterotrophs obtain energy from the food they eat.

autotrophs obtain energy from the sunlight

Describe the three parts of an ATP molecule.

3 Phosphate groups

Use the analogy of battery to explain how energy is stored in and released from ATP.

ATP can be compared to a fully charged battery because both contain stored energy.

Compare the amounts of energy stored by ATP and glucose. Which compound is used by the cell as an immediate source of energy.

- A single molecule of the sugar glucose stores more than 90 times the chemical energy of a molecule of ATP.
- ATP is used as an immediate source of energy.

How were Priestley's and Ingenhousz's discoveries about photosynthesis related?

They both showed that light was necessary for plants to produce oxygen.

Write the basic equation for photosynthesis using the names of the starting and final substances of the process.

6CO2 + 6H20 —> C6H12O6 + 6O2
carbon dioxide + water —> sugars + oxygen

(NOTE: —> is light)

What role do plant pigments plan in the process of photosynthesis?

They gather the sun's energy

Explain the role of NADP+ as an energy carrier in photosynthesis.

It transfers high-energy electrons from chlorophyll to other molecules.

What is the role of ATP synthase? How does it work?

they provide the energy to build energy - containing sugars from low - energy compounds.
It allows hydrogen ions out of the thylakoid

Summarize what happens during the Calvin cycle.

plants use the energy that ATP and NADPH contain to build high-energy compounds that can be stored for a long time.

How do the events in the Calvin cycle depend on the light-dependent reactions?

The Calvin cycle uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars.

Describe three factors that affect the rate at which photosynthesis occurs.

- water
- temperature
- intensity of light

the ability to do work


All living things require...


Autotrophs are plants and some other types of organisms are able to use ________ from the sun to produce _________.

- light energy
- food


Plants and some other types of organisms are able to use light energy from the sun to produce food.


organisms that obtain their energy from food they consume

Energy comes in many different forms. Give examples.

- light
- heat
- electrically
- chemical compounds

Living things use chemical compounds stored and released in cells called...

ATP or adenosine triphosphate

ATP (adenosine triphosphate) contains...

a 5 carbon sugar (ribose) & 3 phosphates

ATP (adenosine triphosphate)

ADP lacks the third phospate make it ...


Cells store the ______ until energy is needed by adding the third phosphate.


When the bond is broken between the 2nd and 3rd phosphate, ______ is released.


The release of energy when the bond is broken between the 2nd and 3rd phosphate power these functions:

- active transport
- muscle contractions
- protein synthesis

The characteristics of ATP make it exceptionally useful as the basic _____ source of cells.


ADP + phosphate —>(energy)—> ATP

Active transport

Sodium (Na) Potassium (K) pump maintaining ions on both sides of the cell

Cells only keeps a small amount of _____ .

- ATP does not store easily

________ stores 90 times more chemical energy than a molecule of ATP.


When plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates (sugar and starches) and a waste product (oxygen).



scientist who concludes the trees gain most of their mass from water


scientist who finds that plants release oxygen


scientist who finds that aquatic plants produce oxygen bubbles in the light but not in dark. Conclusion: plants need light to produce oxygen


scientist who proposed plants convert light energy into chemical energy


scientist who traces chemical path that carbon follows to form glucose (Calvin cycle)


scientist who describes the process of electron transfer from molecule to electron transport chain

Photosynthesis Equation

- Reactants —> Products
- Carbon Dioxide + water in the presence of light yields sugars & oxygen

In addition to water and carbon dioxide, photosynthesis requires ________ and _________, a molecule in chloroplasts.

light and chlorophyll

Light is in ___________ form and creates a spectrum from ________ to ______.

- wavelength form
- violet to red


light absorbing molecules in plants


the principle pigment in plants

2 main types of chlorophyll:

chlorophyll a & chlorophyll b

__________ (green) absorbs the blue-violet and red ends of the spectrum and transfers it to the electrons. While other pigments like __________ absorb the other color.

- Chlorophyll
- carotene

Where does photosynthesis take place?

in chloroplasts

Chloroplasts contain tiny sacs like photosynthetic membranes called...


Thylakoids are arranged in stacks known as ...


Pigments are arranged into clusters known as ...


What are the light collecting units in the chloroplasts?

photosystems (clusters of pigments)

What are the 2 Photosystems reactions?

- (1) light dependent (takes place in the thylakoids)

- (2) light independent or Calvin cycle (takes place in the stroma - the region outside the thylakoid membranes)

Sunlight excites the electrons in ________.


The excited electrons and their energy must be transported by an electron carrier, like _______. This electron carrier can hold ______ electrons and an ion of _________. It is converted into _________ which is trapping sunlight energy into _______ energy. This is the electron ________ _______.

- 2 electrons
- hydrogen (H+)
- chemical energy
- electron transport chain

Light dependent reactions produce _______ ________ and convert _____ and _______ into the energy carriers ______ and _______.

... oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH.

Light independent cycle

takes in the stroma and outside the grana

The Calvin cycle uses ______ and ______ from the light-dependent reactions to produce high energy sugars.


3 factors that affect photosynthesis:

- water supply
- temperature
- intensity of light


organized way of using evidence to learn about the natural world; also, the body of knowledge that scientists have built up after years of using this process


use of one or more of the senses-sight, hearing, touch, smell, and sometimes taste - to gather information


evidence; information gathered from observation


logical interpretation based on prior knowledge and experience


possible explanation for a set of observations or possible answer to a scientific question

spontaneous generation

hypothesis (disproven) stating that life could arise from non-living matter.

controlled experiment

a test of the effect of a single variable by changing it while keeping all other variables the same

manipulated variable

factor in an experiment that a scientist purposely changes; also knows as independent variable.

responding variable

factor is an experiment that a scientist wants to observe, which may change in response to the manupulated variable; also known as a dependent variable.


well-tested explanation that unifies a broad range of observations.


Science that seek to understand the living world.


Collection of living matter enclosed by a barrier that separates the cell from its surroundings; basic unit of all forms of life.


Process by which organisms maintain a relatively stable internal environment.

Sexual reproduction

Process by which cells from two different parents unite to produce the first cell of a new organism

Asexual reproduction

Process by which a single parent reproduces by it self


Set of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes.


A signal to which an organism responds.

Metric system

decimal system of measurement based on certain physical standards and scaled on multiples of 10


Device that produces magnified images of structures that are too small to see with the unaided eye.

Compound light microscope

Microscope that allows light to pass through a specimen and uses two lenses to form an image.

Electron microscope

Microscope that forms an image by focusing beams of electrons onto a specimen.

Cell culture

group of cells grown in a nutrient solution from a single original all.

Cell fractionation

Technique in which cells are broken into pieces and the different cell part are separate


the basic unit of matter

subatomic particles

protons, neutrons and electrons


positively charged particles in the nucleus


particles with no charge in the nucleus


negatively charged particles in constant motion outside the nucleus

why atoms are uncharged

atoms have equal numbers of protons and electrons

chemical element

a pure substance that consists entirely of one type of atom

atomic number

the number of protons in an atom of an element


atoms of the same element that differ in the number of neutrons


substances formed by the chemical combination of two or more elements in definite proportions

chemical formula

shorthand to show the chemical composition of a compound

chemical bonds

hold atoms in compounds together; the main types are ionic and covalent

ionic bond

a bond formed when one or more electrons are transfered from one atom to another


a positively or negatively charged atom

covalent bond

a bond formed when electrons are shared between atoms


a structure that results when atoms are joined together by covalent bonds; the smallest unit of most compounds

van der Waals forces

intermolecular forces of attraction between the oppositely chargeed regions of nearby molecules


H2O; the greatest solvent on earth

oxygen end of the water molecule

slight negative charge because it pulls the electrons more

hydrogen end of the water molecule

slight positive charge because it has less attraction for the electrons

polar molecules

molecules in which the charges are unevenly distributed; they can attract each other


attraction between molecules of the same substance


attraction between molecules of different substances


material composed of two or more elements or compounds that are physically mixed together but not chemically combined


a mixture in which all the components are evenly distributed throughout the mixture


the substance in a solution that is dissolved


the substance in a solution in which the solvent dissolves

ions formed by water molecules

hydrogen ion (H+) and hydroxide ion (OH-)


mixtures of water and nondissolved material


a suspension of water, cells, and undissolved particles that moves through the body

pH 7

pH of pure water

pH scale

a measurement system to indicate the concentration of H+ ions in solution


a compound that forms H+ ions in solution

pH above 7


pH below 7



a compound that produces OH- ions in solution


weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

organic chemistry

the study of all compounds that contain bonds between carbon atoms

organic compounds

carbon compounds

carbon's valence electrons


reasons carbon is important

can make covalent bonds with other atoms (4 valence electrons); can bond to other carbon atoms to make long chains


polymers; molecules made from thousands or even hundreds of thousands of smaller molecules


a process that forms macromolecules by joining smaller compounds together to form larger ones

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