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CHAPTER 8
7TH GRADE
SECTION 1 PG 214-217
I Living Things
A organism- any living thing
B all have similar traits
II Organizing living things
A cell- smallest unit of an organism that carries on
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1. orderly structure and contains instructions
for cellular organisms
2. heredity DNA tells cells what to do
III Growth and Development
A. increase in the number of cells-multicelled
organism
B. growth of a cell larger—1 celled organism
C. development- all changes that take place in a
lifespan
D. lifespan- how long an organism is expected to live
IV Living things must do to live
A. respond- interactive with surroundings
a. stimulus- causes a response
B. maintain homeostasis- regulation of an organisms
life-maintaining condition despite change in
environment
C. use energy
a. from the sun
b. from food
c. from chemicals
D. reproduce
a. keeps organisms group alive
V Living things needs
A. shelter
B. water
C. food
SECTION 2 PG 218-220
I Classification
A. Carolus Linnaeus- developed a new system of
grouping organisms
B. binomial nomenclature- two word naming system
that Linneaus used to name various organisms
C. Genus- group of similar species
D. Species- describes a feature of the species
E. Scientific names are always used so that:
1. avoid mistakes
2. organisms with similar evolutionary history
are put together
3. descriptive information is given in the name
4. helps us organize species
II Modern classification
A. phylogeny- evolutionary history of an organism
and how it has changes over time
B. used to help classify
C. kingdom- largest grouping of organisms and then
becomes more specific Ex: pg 219 fig. 6
III Tools for identification
A. field guides
B. dichotomous keys- key of identifying
characteristics that includes scientific names
Ex: pg 220 Table 1
SECTION 3 PG 221- 230
I Cell Theory
A. Robert Hooke (1165) Look at a cork under
microscope and discovered small box-like structures—
called them cells.
B. Matthias Schleiden (1830) studied plants and said
cells made up plants
C. Theodor Schwann- animals are made of cells.
D. Virchow- cells divide into more new cells.
E. Cell theory1. all living things are made up of cells.
2. the cell is the basic unit of organization in
organisms
3. all cells come from cells
(microscopes page 222-223)
II cell organization (page 224 fig 8)
A. prokaryotic cells- cell without membrane—bound
structures
B. eukaryotic cells -with a membrane—bound
structure
III cell parts (plants, algae, fungi, bacteria)
A. cell wall- tough, rigid outer coverings that protect
cells and give shape
1. cellulose- long thread-like fibers allows
nutrients in and out
2. pectin and lignini. pectin- aids in cell growth, development,
defense, and strength
ii. lignin- makes cell wall rigid
B. cell membrane- protective layer surrounding every
cell
1. outer most covering of a cell unless a cell wall
is there
2. regulates interactions between cell and its
environment
3. nutrients in----wastes out
C. cytoplasm- gelatin-like substance that flows in a
cell.
1. most life processes occur here
2. cytoskeleton- framework made of tubes of
protein
D. ribosomes- structures that make proteins
1. float freely in cytoplasm
2. DNA tells ribosomes how, when and what
order to make proteins
E. organelles- found only in eukaryotic cells
F. nucleus- directs all cell activities of the cell
1. contains the DNA
G. chloroplasts- contain chlorophyll- a green pigment
1. found only in plant cells
2. changes sunlight, water, and CO ---- O and
sugar
H. mitochondria- store and release energy
1. contain ribosomes
I. endoplasmic reticulum- a series of folded
membranes so materials can be processed and
move around the cell
1. extends from the nucleus to cell
membrane
2. ribosomes are attached to it
K. golgi body- sorts proteins and other cellular
substances and packages them into vesicles
1. vesicles deliver cellular substances
to areas inside the cell
L. vacuoles- stores cell material, water, wastes,
and food.
1. vacuoles make up most of a plant
cell volume
M. lysosomes- breakdown food molecules,
wastes, and old cell parts
1. recycles parts
2. kills viruses and bacteria that enter
The cell
IV Organization of organisms (many-celled)
A. cell
B. tissue- group of similar cells
C. organ- made of 2 or more tissues that work
together
D. organ system- group of organs that work to
perform a specific function
I Virus
A. a strand of hereditary material surrounded
by a protein coating
B. It will replicate itself with the help of a
living cell
C. have no nucleus, organelles, or cell membrane
II 2 types of viruses
A. active virus
a. enters cell and causes host cell to make
new virus
b. kills host cell (page 232 fig. 17)
B. latent virus
a. inactive virus
b. enters the cell, and its hereditary
material becomes part of the cell’s
hereditary material
c. the virus is copied along when new cells
are made
d. lays dormant or quiet until something
triggers it Ex: cold sore
III Virus affect
A. Can only infect certain cells (human or
animal)
B. A few can affect more than 1 type of cell
C. Bateriaphages- viruses that infect bacteria
IV Treatment
A. antibiotics- treat bacterial infections but
don’t work on viruses
B. anti-virals- used on viruses- side effects are
terrible
C. Prevention
a. Vaccination
b. Sanitation
c. Quarantine
d. Animal control
D. Natural immunity- making interferonsproteins that protect cells from viruses
a. Proteins are produced rapidly by
infected cells and move noninfected
cells host—noninfected produced
protective substances
E. Vaccines-cause the body to make
interferons-usually weakened virus is given
(Jenner 1796)
F. Gene therapy- fixes cells that are defective
because of heredity
a. virus injected that have correct
heredity
b. Ex: AIDs/HIV currently being studied
this way