science book a: chapter 3

Chapter: Cell Processes

Table of ContentsTable of Contents

Section 3: Energy for Life

Section 1: Chemistry of Life

Section 2: Moving Cellular Materials

• Matter - anything that has mass and takes up space.

• Energy - anything that brings about change.

The Nature of Matter

Chemistry of LifeChemistry of Life

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• Nucleus - center of atom

• contains protons and neutrons (equal mass)

Atoms

Chemistry in LifeChemistry in Life

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Click image to view movie.

• Proton (+)• Neutron ( )• Electron (-)

•orbits nucleus

• Electrons - involved in chemical reactions.

• Atom - mostly empty space

Atoms


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• Element

• made of one kind of atom

• in most simple form

• each has a 1 or 2 letter symbol

Elements


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• Periodic table

• Mass

• # of Protons

• Symbol

Elements


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Elements


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• Compounds - made of two or more elements

Compounds and Molecules


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• There are two types of compounds— molecular compounds and ionic compounds.

• Molecular compound

• Made of molecules held together by chemical bonds

• Share outermost electrons

• Have different properties than atoms alone

Molecular Compounds


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Molecular Compounds


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• Chemical reactions

• chemical bonds break

• atoms rearranged

• new molecules form

• Ions

• Electrically charged atoms

• Formed when atoms combine after becoming (+) or (-)

Ions


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• Ionic Compound – molecule held together because of opposite charges attracting one another

• One atom loses electron(s)

• Another atom gains electron(s)

• Their charge holds them together

Ionic Compounds


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• Mixture - combination of substances in which individual substances retain their own properties

• Can be solids, liquids, gases, or any combination

Mixtures


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• Solution - 2 or more substances mixed evenly

Mixtures


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• Suspension

• substance evenly spread throughout

• Will sink to bottom after time

Organic Compounds


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• Organic Compounds

• always contain carbon and hydrogen

• usually are associated with living things.

• Inorganic Compounds• make up nonliving things

Organic Compounds


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• Carbohydrates

• organic molecules that supply energy for cell processes

• Sugars and starches

• Also part of cell structures

Carbohydrates


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• Lipids

• do not mix with water

• Fats and oils

• Large amounts of energy

• Part of cell membrane

Lipids


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• Enzymes

• Proteins that regulate chemical reactions

• Proteins

• made of amino acids

• building blocks of cellular structure

Proteins


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• RNA

• ribonucleic acid

• needed to make enzymes and proteins.

Nucleic Acids


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• DNA

• deoxyribonucleic acid

• contains genetic material

• Can contain the elements nitrogen, phosphorus, and sulfur.

Inorganic Compounds


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Importance of Water


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• can live for weeks without food

• only a few days without water.

• all the chemical reactions in living things take place in water solutions

• most organisms use water to transport materials

Importance of Water


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Characteristics of Water


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• Negative part of a water molecule is attracted to the positive part of another water molecule

• temperature of water changes slowly

• acts like insulation



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• water freezes - ice crystals form

• Ice floats – insulates water below



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Question 1

Answer

_______ is anything that has mass and takes up space.

The answer is Matter. Everything in your environment is made of matter.

Section CheckSection Check

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Question 2

Answer

A(n) _______ is made up of only one kind of atom.

The answer is element. An element can’t be broken down into a simpler form by chemical reactions.


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11Section CheckSection Check

Question 3Which best describes the structure in this illustration?

A. atomB. elementC. molecular compoundD. ionic compound


Answer

The answer is C. Molecular compounds form when different atoms share their outermost electrons.

Passive Transport

Moving Cellular MaterialsMoving Cellular Materials

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• Cell’s membrane - selectively permeable

• allows some things to enter or leave and keeps other things in or out

Passive Transport


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• Passive transport - movement of substances through the cell membrane without the use of energy

• 3 Types

• Diffusion

• Osmosis

• Facilitated diffusion

Diffusion


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• Diffusion - movement of molecules from an area of high concentration to an area of low concentration

• Equilibrium – when molecules become concentrated equally in all areas

Osmosis—The Diffusion of Water

• Osmosis - the diffusion of water through a cell membrane is called.


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Facilitated Diffusion• The movement of large molecules through a

membrane with the help of transport proteins


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Active Transport


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• Active transport - energy is needed to move materials through a cell membrane against the concentration gradient

Endocytosis and Exocytosis• Endocytosis -

process of taking substances into a cell by surrounding it with the cell membrane


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Endocytosis and Exocytosis• Exocytosis - process of taking substances OUT

of a cell by surrounding it with the cell membrane


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Question 1

What is diffusion?


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Diffusion is the type of passive transport in which molecules in a more dense area randomly move to an area that is less dense until equilibrium is reached.

Answer

Question 2

Answer

_______ is the diffusion of water through a cell membrane.

The answer is osmosis. Cells contain water and are surrounded by water. These water molecules move by diffusion into and out of cells.


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Question 3

Which carries oxygen throughout your body?

A. red blood cellsB. white blood cellsC. sex cellsD. none of the above


Answer

The answer is A. Oxygen molecules from the lungs diffuse into red blood cells which carry oxygen throughout your body.

Trapping and Using Energy• Metabolism - The total of all chemical

reactions in an organism is called.

Energy for LifeEnergy for Life

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Trapping and Using Energy• Enzymes

• Cause chemical reactions

• Can be used over and over


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Click image to view movie.

Photosynthesis• Producers -

Organisms that make their own


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• Consumers - Organisms that cannot make their own food

Photosynthesis


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• Photosynthesis uses light energy to make sugars (chemical energy), which can be used as food.

• Chlorophyll – green pigment found in chloroplasts that performs photosynthesis


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Storing Carbohydrates

• Excess sugar made is stored as starches or other carbohydrates


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Respiration

• Cellular respiration – changes chemical energy into useable energy

• Movement, heat, etc.

• Requires oxygen


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Breaking Down Carbohydrates• Carbohydrates Glucose Useable energy

Cellular Respiration:


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Fermentation• Fermentation

– releases smaller amount of energy when oxygen is not present


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• Occurs only in cytoplasm (not mitochondria)

Question 1

Answer

_______ is the total of all chemical reactions in an organism.

The answer is metabolism. All of the activities of an organism involve chemical reactions in some way.


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Question 2

Which does this equation represent?

A. respirationB. fermentation

C. photosynthesisD. chemosynthesis


Answer

The answer is C. During photosynthesis, plants take in carbon dioxide and water and combine it with light energy to make sugars, which they use for food.

Question 3

Answer

_______ is the type of food molecules most easily broken down by cells.

The answer is carbohydrates. As carbohydrates are broken down, energy is released.


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science book a: chapter 3

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