7th Grade
TEST Review
Commonality of Living Things:
• Living things are made of one or more
cells.
• Living things need to acquire energy.
• Living things grow and develop.
• Living things contain DNA.
• Living things must reproduce in order to
continue the species.
• Living things respond to stimuli.
Scientific Classification:
Living things are grouped according
to many characteristics. The twopart scientific name given to living
things includes the Genus and
Species. The Genus is always
capitalized, and the species is
always lower case.
(example: Tyrannosaurus rex)
Scientific Classification:
Within this classification system, there are 6
Kingdoms:
1) Animals –consumers; includes everything
from insects to fish to coral to humans; use
cellular respiration
2) Plants – producers; use photosynthesis
3) Fungi – mushrooms, lichen, yeast; grows on
their food.
4) Protists – “oddball” kingdom; some have
similarities of both plants and animals.
5) Eubacteria – single celled organisms; most
plentiful organisms on Earth; found
everywhere from cheese to our bodies;
prokaryotes.
6) Archebacteria – single celled organisms that
live in harsh environment s; prokaryotes.
Prokaryotes: a singlecelled organism that
does NOT have a
nucleus. DNA floats
freely within the
cytoplasm.
(“Pro” – “No”)
Eukaryotes:
Organisms that
contain cells having a
nucleus enclosed by a
membrane.
Eukaryotic cells have specialized organelles:
Animal cells:
Mitochondria is known as the ‘powerhouse’ of the
cell.
Nucleus is the control center and contains the DNA.
Eukaryotic cells have specialized organelles:
Plant cells have:
Cell Walls - give support
Chloroplasts - for photosynthesis (process a plant
uses to make its own food) and green color
Vacuole – storage compartment for fluid and wastes
Cellular Respiration vs. Photosynthesis
Photosynthesis: Carbon dioxide + water + light energy = glucose + oxygen
Cellular Respiration: glucose + oxygen = carbon dioxide + water + energy
*Notice that these two processes are opposite.
Autotroph (Producer):
Organism that makes its
own food. (example: a
plant uses photosynthesis)
Heterotroph (Consumer):
Organism that acquires
energy by eating other
organisms or their byproducts. (example:
animals eat plants or other
animals)
Sexual Reproduction vs. Asexual Reproduction
• 2 parents
• Offspring is
combination of
both
parents/unique
• 1 parent
• Offspring is an
exact copy
(clone)
NOTE: Animals can reproduce sexually (humans) or
asexually (Black worms). Plants can reproduce both
sexually and asexually. Bacteria is the only kingdom
that reproduces asexually exclusively.
Biotic (Living)
Animals
Trees
Plants
Cells
Bacteria
Protists
Fungi
vs. Abiotic (Nonliving)
Rocks
Soil
Air
Water
Climate
Temperature
Sun
Mitosis
• Body Cells (Non
Reproductive)
• Cell division that
produces a new
cell identical to the
parent cell.
(example: skin cells
undergo mitosis in
order to make new
skin cells.)
vs.
Meiosis
• Sex Cells
(Reproductive
Cells)
• Cell division that
produces a new
cell with half the
number of
chromosomes.
(Note: ONLY sex
cells – egg and sperm
– undergo meiosis.)
Mitosis begins AND ends with diploid cells – cells that
contain all their chromosomes.
Meiosis begins with diploid cells but ends with haploid
cells – cells that contain HALF the number of chromosomes.
Meiosis results in 4 haploid cells.
Reproductive
cells (egg and
sperm) always
have half the
number of
chromosomes
than body cells!
These cells with
half the number
of chromosomes
are called
haploid cells.
20
10
10
10
10
*If an animal’s skin cells have
20 chromosomes, their egg or
sperm cells will contain 10.
Chromosomes are compressed strands of DNA that contain
the genetic codes for traits. We inherit one chromosome
from mom and one chromosome from dad to create a pair.
Chromosomes are like SOCKS! They come in PAIRS!
Humans have 46
chromosomes (23
pairs) with one
chromosome from
each pair being
inherited from each
parent. Males are
XY; Females are XX.
Therefore, males
determine the
gender of the
offspring.
Punnett Squares
Punnett Squares are
used to illustrate the
possible gene
combinations of
offspring from
particular parents.
Simply add rows and
columns together to get
the outcomes.
Genetics
Alleles = single traits represented
by either capital or lowercase
letters (T or t)
Dominant = trait that dominates or
covers up recessive traits if present;
Identified by a capital letter.
Recessive = trait that is covered up
by the dominant trait unless there
is no dominant trait present;
Identified by a lower case letter.
Genotypes = gene combination
(Hh, hh, HH)
Phenotypes = physical
characteristics (green pea, brown
hair, tall, freckles, etc.)
Homozygous –
gene
combination
containing the
same traits
Heterozygous –
gene
combination
containing
different traits
BB or bb
Bb
Mendel’s 3 Laws
2
Law of
Segregation: Allele
pairs separate or
segregate during
gamete formation,
and randomly
unite at
fertilization.
1
Law of Dominance:
The dominant trait
will be expressed
whenever there is a
dominant allele
present.
3
Law of Independent Assortment: Traits are
transmitted to offspring independently of one
another.
DNA
• DNA is a DOUBLE HELIX.
• DNA has 4 Nucleotide bases:
Adenine, Thymine, Guanine,
Cytosine.
• A always binds with T, and G
always binds with C.
(Remember to meet AT Gigi’s
Cupcakes!)
• The backbone of DNA is made
of deoxyribose sugar.
• Watson and Crick are
responsible for proposing this
model.
RNA
• RNA is a SINGLE HELIX.
• RNA has 4 Nucleotide bases:
Adenine, Uracil, Guanine,
and Cytosine.
(They are the same as
DNA
except that Uracil replaced
Thymine.)
• The backbone of RNA is
made of ribose sugar.
• A binds with U, and G binds
with C.
Human Body System
Cells make up tissue. Tissue make up organs. Organs make
up systems. All the systems work together to maintain life
and a state of homeostasis.
Circulatory System (Closed-circuit)
The heart gets oxygenated
blood from the lungs and
sends it to all the body via
arteries.
(“Arteries - Away”)
The blood returns to the
heart via veins and picks up
carbon dioxide as it goes.
(“Veins – To”)
Capillaries are the smallest
vessels that connect
arteries with veins.
Life is in the BLOOD
White blood cells – fight infection
Red blood cells – deliver oxygen to the body and
CO2 to the lungs
Platelets – form clots to prevent bleeding
Plasma – liquid part of blood; mostly water
Respiratory System
Gas exchange takes place in the alveoli of the lungs.
This system breaks down food mechanically (teeth,
tongue) and chemically (enzymes, acids) in order to
get food small enough to be absorbed by the body
for nutrition.
Most digestion occurs in the small intestine. Waste
is compacted and liquids reabsorbed from
undigested foods in the large intestine.
Nervous System: The Brain, Spinal Cord, & Nerves
The Nervous System
uses nerve cells to send
and receive sensory
signals. (sight, smell,
hearing, touch, taste)
Speciation is the evolutionary process by which
new biological species arise. This may occur
because of geographic isolation, climate differences,
dietary needs, genetic mutations, etc.
Many symbiotic relationships exist in nature:
Mutualism – both organisms benefit
Commensalism – one organism benefits while the
other is unaffected
Parasitism – one organism (parasite) benefits while
the other (host) is harmed