1. Cells Unit Chapter 6: Chemistry in biology
Chapter 7: Cellular structure and function
Chapter 8: Cellular energy
Chapter 9: Cellular Reproduction

2. 6.1 Atoms, Elements, & Compounds
Chemistry will help you learn about biology because organisms are made up of different chemicals.
Everything is made
up of matter and
matter is made up
of atoms.
Atoms are the smallest
chemical units of matter.

3. 3 kinds of particles The nucleus is the core part of an atom Proton
Positive charge (+)
Found in the nucleus
Electron
Negative charge (-)
Travels around the nucleus
Neutron
Neutral charge

4. Elements
A scientist named Mendeleev created the Periodic Table which lists all of the known elements on Earth
An element is a pure substance made of only one kind of atom
Each element is represented by a one or two letter symbol

5. Common elements include carbon, oxygen, hydrogen, helium, nitrogen…
Elements differ in the number of protons their atoms contain.
Hydrogen only contains one proton
Oxygen contains eight protons
How many protons does uranium have?

6. Atomic Number and Atomic Mass
Atomic number tells us
how many protons are in
an element.
Atomic mass tells us
how many protons and
neutrons are in the nucleus
(how heavy the element is)

7. Compounds A stable substance made up of two or more elements.
Every compound is represented by a chemical formula. Each element may have a subscript that tells how many there is of that element.
Water H2O
H= white
O= red

8. How to count #’s of elements in compounds
Examples:
salt (NaCl, 1 sodium and 1 chlorine)
water (H2O, 2 hydrogen and __ oxygen)
carbon dioxide
(CO2, __ carbon and __ oxygen)
sugar
(C6H12O6, __ carbon, __ hydrogen __ oxygen)

9. Bonding (2 types)
Covalent bond – when two or more atoms share electrons and form a molecule.
A molecule is a group of atoms put together.
The number of protons found in the nucleus should equal the number of electrons floating around the nucleus. This makes an element stable.

10. Ionic Bond – A bond formed between molecules when electrons are transferred.
Sometimes atoms or molecules gain or lose electrons
This transfer causes one atom to be positive and one atom to be negative. When combined they form a stable molecule (like salt, NaCl).

11. 6.2 Chemical Reactions
Chemical reactions allow living things to grow, develop, reproduce, and adapt.
Chemical reaction – process by which atoms or groups of atoms in substances are reorganized into different substances.
Energy is the ability to move or change matter.
Energy can be stored or released by chemical reactions.

12. glucose and oxygen react to form carbon dioxide and water
Chemical Equations
The starting materials for a chemical reaction are called reactants.
The newly formed substances created after a reaction are the products.
REACTANTS  PRODUCTS
C6H12O O  CO H20
glucose and oxygen react to form carbon dioxide and water

13. Circle the reactant(s) and box the product(s)
H2O + NaCl (salt) > Na+ + Cl-
H2CO3 (carbonic acid) < H2O + CO2
HCl + NaOH > NaCl + H2O

14. Balanced equations
In chemical reactions, matter cannot be created or destroyed.
This means that the number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side.
Balance this equation:
C6H12O O  CO H20

15. Energy of Reactions
Living things cannot undergo chemical reactions without energy.
Activation energy – the maximum amount of energy needed for reactants to form products in a chemical reaction.

16. Enzymes
Enzymes are proteins that speed up chemical reactions in the body by lowering the activation energy.
Enzymes are never used up in the reaction. They can be used again and again.

17. Lock-and-Key Model of Enzymes
The reactants that bind to the enzyme are called substrates.
The specific location where a substrate binds on an enzyme is called the active site.

18. Factors that Affect Enzyme Function
Enzymes operate best within certain temperature ranges. Temperatures outside this range make the reaction move slowly or not at all.
Enzymes operate best within a certain range of pH values. Too low of a pH (acidic) or too high of a pH (basic) will slow or stop a reaction.

20. 6.3 Acids and Bases
Acids – any substance that releases hydrogen ions (H+) when dissolved in water.
Bases – any substance that releases hydroxide ions (OH-) when dissolved in water.
The amount of hydrogen or hydroxide ions determines the strength or weakness of the substance.
The pH scale is used to determine if a substance is an acid or base.

21. The pH scale ranges from
0 to 14.
Acids have values from
0 – 6.
Bases have values from
8 – 14.
Anything with a value of 7 is considered neutral.

22. 6.4 Carbon Compounds
Carbon compounds are also known as organic compounds.
They make up most of what living things are made of.
These compounds are made up of many carbon molecules covalently bonded to each other and to other elements (usually hydrogen & oxygen)

23. Carbohydrates also known as sugars
made up of carbon, hydrogen and oxygen molecules in a ratio of 1:2:1
glucose is a common biological sugar (C6H12O6)
examples: sucrose, lactose, glycogen, cellulose
functions: provide energy, structural support

24. Lipids include fats and oils they do not dissolve in water
made up of lots of carbon and hydrogen connected in long chains
examples: phospholipids, steroids
functions: store energy, provide support, insulation

25. Some lipids contribute to cardiovascular disease by lining the blood vessels with plaque.
Plaque build up can block blood flow causing a stroke or heart attack.

26. Proteins made up of smaller molecules called amino acids
enzymes are a type of protein used to speed up chemical reactions.
salivase is an enzyme in the mouth that helps to break down food that you chew
lactase is an enzyme in the stomach that helps to break down lactose found in dairy products
functions: transport substances, speed reactions, structural support, control cell growth

27. Nucleic Acids made up of smaller molecules called nucleotides
nucleotide = sugar + phosphate + base
examples: DNA, RNA
function: store and transmit genetic information

28. 7.1 Cell Discovery and Theory
Robert Hooke discovered cells using a simple microscope in He called them cells because they reminded him of small rooms where monks live.

29. Cell Theory
In 1838, Matthias Schleiden and Theodor Schwann concluded all living things are made of one or more cells.
In 1855, Rudolph Virchow proposed all cells come from other living cells.
Many years later, scientists concluded that cells give living organisms structure.

30. Characteristics of Microscopes
Since cells are not able to be seen by our eyes, we need microscopes to magnify them.
Microscopes enable biologists to examine the details of cell structure and to understand how organisms function.

31. Types of Microscopes
Compound Light Microscopes have a low magnification and can be used to examine living cells.
Electron Microscopes have a high magnification but cannot be used to examine living cells.
Scanning Tunneling Microscopes use a computer to generate a three-dimensional image of the object.

32. Basic Cell Types
Prokaryotic cells are the smallest and simplest cells on Earth. The best example of a prokaryote is bacteria.
Characteristics of Prokaryotes
surrounded by a cell wall
DNA moving freely inside the cell
some have flagella to help them move
don’t have a nucleus

33. Eukaryotic cells are larger and more complex
Eukaryotic cells are larger and more complex. They have a nucleus and other organelles.
Cell Animation

34. 7.2 Cell Membrane
The cell membrane helps to maintain a cell’s homeostasis.
The cell membrane is selectively permeable meaning it allows only certain substances into and out of the cell.
The cell membrane is made up of a double fat layer called a phospholipid bilayer.
Draw a diagram of a cell membrane in your notes.

36. Membrane Proteins Proteins in cell membranes include:
enzymes which help with chemical reactions inside the cell
receptor proteins which pull substances into the cell when the cell needs it
transport proteins which help move substances across the membrane either into or out of the cell

37. 7.3 Organelles
cytoskeleton: eukaryotic cells have a cytoskeleton of microscopic protein fibers that provide structure and support for the cell and its organelles
nucleus: tells the cell what to do and stores DNA
the nucleus is surrounded by a double membrane called the nuclear envelope that helps protect the DNA inside
when a cell prepares to divide, the DNA inside the nucleus forms chromosomes. This helps genetic information get transferred from the old cell to the new cell.

38. Production of Proteins
proteins are made or created inside ribosomes which are found on another cell organelle called the endoplasmic reticulum (ER)
proteins are important because they help with chemical reactions
Distribution of Proteins
proteins must be programmed so they know what job to perform inside the cell
the Golgi apparatus is the organelle that programs proteins

39. Lysosomes Mitochondria
some proteins are special because they help breakdown and digest substances inside the cell
Mitochondria
make and store energy from carbon compounds (carbohydrates, lipids, proteins)
The energy stored is ATP
Which types of body cells would need the most mitochondria to make energy for the body?

40. Structures in Plant Cells
Cell Wall
used for support and protection
maintains an upright shape for all plants
Chloroplasts
structures that give plants their green color
help to capture energy from the Sun to make food
Central vacuole
used to store excess water for the plant when the environment gets dry
also helps give a plant it’s shape

42. 7.4 Cellular Transport
Cells have to maintain a stable internal environment in order to survive. We call this homeostasis.
Cells are constantly bombarded by their external environment.
The cell membrane’s job is to control what goes in and what comes out of the cell.

44. Passive Transport
Passive transport - when something passes through the cell membrane without using any energy
Equilibrium – state of balance when a substance on one side of the cell membrane equals the amount on the other side
Concentration gradient – when one side of the membrane has a higher concentration of substances than the other side

45. Diffusion
Particles or substances inside and around the cell constantly move.
Diffusion – when substances move from an area of high concentration to an area of low concentration.
The cell does not have to use any energy for a substance to diffuse into or out of a cell.
Remember that the cell membrane is selectively permeable; that means it only allows certain substances to pass through.

47. Facilitated Diffusion
Most cells have membrane proteins embedded in their cell membrane that help to bring in or carry out substances.
A carrier protein is a molecule that typically carries amino acids and sugars across the cell membrane. (too big to move on their own).
Another word for facilitate is “to help”.
The cell does not have to use any energy for a substance to diffuse into or out of a cell.

49. Osmosis
Osmosis is the diffusion of water across a selectively permeable membrane.
Water is always needed by the cell, so it passes easily through the cell membrane.
A cell always wants to be stable, so water will move into and out of a cell until the inside of the cell is neutral (pH of 7)

50. How does water move?
There are three possibilities for the direction of water movement across a cell membrane:
Water moves out
Water moves in
Water does not move

51. Isotonic Solutions
When water is equal on either side of the cell membrane, there is NO MOVEMENT of water into or out of the cell.
The cell shape remains unchanged.
This is the condition most cells try to maintain in order to survive.

52. Hypotonic Solutions
When the concentration of water outside of the cell is greater than inside the cell, the water MOVES INTO the cell.
When water moves in, the cell swells and sometimes bursts.
Because plant cells are more rigid than animal cells, they typically don’t burst.

53. Hypertonic Solutions
When the concentration of water outside of the cell is less than inside the cell, the water MOVES OUT of the cell.
When water moves out, the cell shrinks.

55. Active Transport
Active transport requires the cell to use energy to move substances against a concentration gradient.
The energy the cell uses is ATP.
Substances have to move from an area of low concentration to an area of high concentration.
Swimming pool, going up a down escalator, kayaking demo...

56. Types of Active Transport
Proteins and large sugars are too large to pass through the membrane or be moved by membrane proteins.
These substances are moved across a cell membrane by vesicles (large pockets in the cell membrane).
Draw diagrams in your notes
active transport demo

58. 8.1 Obtaining Energy
In order for your body to function properly, you need energy to perform daily activities.
All energy comes from the Sun.
Autotrophs make their own food by using the Sun’s energy
Heterotrophs need to ingest food to obtain energy

59. Metabolism
Metabolism – all the chemical reactions that take place in a cell
Two important chemical reactions involve:
photosynthesis
cellular respiration

60. ATP
Adenosine triphosphate is the most important biological molecule that provides energy for living things.
ATP releases energy when the bond between phosphates is broken.

61. 8.2 Photosynthesis
Photosynthesis – describes the process of how the Sun’s energy is trapped and converted into energy
Overall equation:
SUNLIGHT
6CO H2O  C6H12O O2
Plants have special organelles called chloroplasts that help to capture the Sun’s energy.

63. 8.3 Cellular Respiration
Cellular respiration – describes the process of how living organisms obtain energy by breaking down organic molecules
Overall equation:
C6H12O O2  6CO H2O + energy
Animals have special organelles called mitochondria that help to breakdown sugars into useable energy.

64. 2 1
glucose
and oxygen
carbon dioxide
and water 3 5 4

65. 9.1 Cellular Growth
Cell size is limited by its ratio of surface area to its volume.
Surface area – the area covered by the cell membrane.
Volume – space taken by the inner contents of the cell.

66. Importance of Small Cell Size
As a cell grows, its volume increases much more rapidly than the surface area.
By remaining small, cells can function better.
Substances can move in and out easily
The cell can communicate across smaller distances

67. The Cell Cycle
Once a cell reaches its size limit, something must happen—either it will stop growing or it will divide.
Most cells will eventually divide.
Cell cycle – a repeating sequence of events that allow a cell to grow and divide.

68. How do cells know when to divide?
Just as traffic lights control the flow of traffic, cells have a system that controls the phases of the cell cycle.

69. Cells have a number of “red light-green light” switches that regulate information traveling through the cell.
Cells can’t divide unless they pass all checkpoints with green lights.
Yellow or red lights would slow or stop cell division.

70. Stages of the Cell Cycle

72. Chromosomes
How many cells do you think are produced by the human body everyday?
2 trillion cells, that’s 25 million cells every second
Why do cells divide?
Cells need to grow, develop and repair themselves
When a cell divides, the DNA must be copied before the genetic information is distributed

73. Prokaryotic Cell Reproduction
Bacteria have a single circular strand of DNA that “floats” around the cell; the DNA is not contained within a nucleus
Prokaryotes reproduce by a type of cell division called binary fission.

74. Binary Fission

75. Eukaryotic Cell Reproduction
In eukaryotes, DNA is organized into units called genes
Genes are small segments of DNA
A single molecule of DNA has thousands of genes lined up next to each other

76. Chromosomes
When a cell prepares to divide, the DNA coils up into a structure called a chromosome.
Each chromosome has two strands; each strand is an exact copy of the other.
Each individual strand is called a chromatid.
The two chromatids are connected by a point called a centromere.

77. Chromosome Structure
Homologous chromosomes are those that are identical in structure.
Most humans have 23 pairs of chromosomes (46 total).
There are two types of cells: somatic (body cells) and gametes (sex cells).

78. Cancer
Sometimes cells have mutated chromosomes that lead to cancer. These cancer cells can change all the checkpoints to green lights and they coast through the cell cycle reproducing rapidly.
All cancers are different, but if scientists can figure out what changes all the checkpoints to green lights we could cure cancer.

79. Causes of Cancer
Carcinogens – substances that are known to cause cancer.
Asbestos
Tobacco products
Ultraviolet radiation and other forms of radiation
Genetics