Download Ch. 2A – Structure and Function - Spring

Ch. 2A – Structure and Function
Lesson 1 – Cells and Life
(pgs. 42-47)
*Scientists whose discoveries led to the development of Cell Theory:
Robert Hooke – English scientist who used a microscope to view cork cells; gave cells their name (1665)
Anton van Leeuwenhoek – Dutch scientist who viewed unicellular organisms in pond water (1674)
Matthias Schleiden – German scientist who looked at plant cells (1838)
Theodor Schwann – German scientist who looked at animal cells (1839)
Rudolph Virchow – German doctor who proposed all cells come from preexisting cells (1855)
Cell Theory:
1. All living things are made of one or more cells.
2. The cell is the smallest unit of life.
3. All new cells come from preexisting cells.
Basic Cell Substances
*Water
 main ingredient in any cell; makes up 70% or more of a cell’s volume
 surrounds cells
 helps maintain homeostasis by insulating cells
 dissolves substances so they can move into and out of cells
*Macromolecules – substances formed by joining many small molecules together, like cars of a
train; enable cells to function
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Nucleic acids – long chains of nucleotides joined together; contain genetic information
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Proteins – long chains of amino acid molecules; play a role in structural support,
transport, chemical breakdown of substances, and communication in a cell
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Lipids – large macromolecules that do not dissolve in water; play a role in energy
storage, protective membranes, and communication in a cell
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Carbohydrates – made up of one, two, or a long chain of sugar molecules; play a role in
energy storage, structural support, and communication in a cell
Lesson 2 – The Cell
(pgs. 50-57)
(Ch. 2A - Structure and Function continued…)
Cell Shape and Movement
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Cell membrane – flexible covering that protects the inside of the cell from the environment
outside the cell
Cell wall (plants, fungi, bacteria, some protists) – a stiff structure outside the cell membrane
Cell appendages
o Flagella – tail-like appendages that whip back and forth to move the cell
o Cilia – short, hair-like structures that move a cell or move molecules away from a cell
Cytoplasm – fluid inside a cell that contains salts and other molecules
Cytoskeleton – network of threadlike proteins that are joined together to form a framework
inside the cell to give it shape and help it move
Cell Types
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Prokaryotic – cells without a nucleus; genetic material is not surrounded by a membrane; most
are unicellular (ex. bacteria cells)
Eukaryotic – cells have a nucleus; genetic material surrounded by a membrane; larger than
prokaryotic cells (ex. plants, animals, fungi, protists)
Organelles – structures in cells surrounded by membranes; have specialized functions
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Nucleus – part of a eukaryotic cell that directs cell activities and contains genetic information
stored in DNA (which is organized into structures called chromosomes)
o Nucleolus – found in the nucleus; makes ribosomes
Manufacturing Molecules
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Ribosomes – make proteins; not surrounded by a membrane
Endoplasmic reticulum (ER) – spreads from nucleus throughout most of the cytoplasm
o Rough – has ribosomes on its surface
o Smooth – no ribosomes; makes lipids such as cholesterol and helps remove harmful
substances from the cell
Processing energy
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Mitochondria – release energy during chemical reactions; this energy is stored in high-energy
molecules called ATP
o ATP – fuel for cellular processes like growth, cell division, and material transport
Chloroplasts (plants and some protists) – membrane-bound organelles that use light energy to
make food – a sugar called glucose, which contains stored energy—from water and carbon
dioxide in a process known as photosynthesis
Processing, Transporting, and Storing Molecules
 Golgi apparatus – prepares and packages proteins into vesicles; looks like a stack of pancakes
o Vesicles – tiny, ball-like organelles that transport substances from one area of a
cell to another
 Lysosomes (animal cells) – contain substances that help break down and recycle cellular
components
 Vacuoles – organelles that store food, water and waste material; plant cells usually have one
large vacuole; some animal cells have many small vacuoles