Transcript Seventh Grade Review - PAMS-Doyle

Seventh Grade
Review
Life Science
Living organisms require
food, water, shelter, energy,
and space to survive
Cells are the smallest units
that carry out activities of
life
The cell membrane forms the outer boundary of the
cell and only allows certain things to enter and exit
Cytoplasm is the gel-like material inside the cell
The cell wall is located outside of the cell membrane
and is used to support and protect the cell found in
plants, monerans, and fungi.
The nucleus directs all of the activities of the cell
and contains all of the genetic blueprints for the
operations of the cell
The endoplasmic reticulum acts as the highway
system of the cell and moves materials around the
cell, Golgi bodies of the cell packages materials to
be moved to the outside of the cell
The mitochondria of a cell are the powerhouse of the
cell that breaks down food molecules and produces
energy for the cell
Lysosomes of a cell digest and destroy waste
products and worn-out cell parts. Vacuoles are
temporary storage units for the cells that may
contain food, water, or waste
Ribosomes make proteins for the cell
The differences between plant cells and animal cells
are: plant cells have chloroplasts, cell walls, and
larger vacuoles. Animal cells have centrioles during
mitosis
• Similarities and differences in plants and
animals are evident at the cellular level.
Plant and animal cells contain some of the
same organelles and some that differ.
Chloroplasts are organelles in plant cells that
transform light energy into chemical energy in the
form of sugar
CH O
6
12
6
glucose
Cell Theory
• The development of cell theory can be
attributed to the major discoveries of
many notable scientists. The
development of cell theory has been
dependent upon improvements in the
microscope technologies and
microscopic techniques throughout the
last four centuries.
Cell Theory

Cell theory includes the following
components: all living things are composed
of cells; cells are the smallest unit
(structure) of living things that can perform
the processes (functions) necessary for life;
and living cells come only from other living
cells.
Anton van Leeuwenhoek, in the mid 1600’s,
created a simple microscope, and with a
tiny glass bead for a lens
Robert Hooke, in 1665, looked at slices of
cork under his microscope, and called the
“empty boxes” he saw cells
In 1839, Matthias Schleiden, studied
plants and concluded that all plants
were made of cells
In 1839, Theodor Schwann, studied animals
and concluded that all animals were made
of cells
Rudolph Virchow, in 1856,
hypothesized that older cells divide
to form new cells
The three components of the
cell theory are:
• 1) all organisms are made up of
one of more cells
• 2) cells are the basic unit of
structure and functions in all
organisms
• 3) all cells come from cells that
already exist
Cell Reproduction
• Mitosis is the process in which the
nucleus of a cell divides and
replicates to form two identical
nuclei in a series phases:
prophase, metaphase, anaphase,
and telophase
• Meiosis is the process of division in
cells that produces sex cells
Interphase
Interphase is not part of mitosis but is included
here as a reminder that interphase preceeds mitosis.
Prophase
Metaphase
Anaphase
Telophase
Cell Reproduction
• The purpose of mitosis is to
produce new cells for growth and
repair that are identical to the
parent cell. The purpose of meiosis
is to produce reproductive (sex)
cells that carry half the genetic
material of the parent
Differentiate between the purpose of
mitosis and meiosis
Cells that have the same goal group
together to form tissues, tissues that have
the same goal group together to form
organs, organs with similar goals group to
form organ systems
Unicellular organisms are
made of only one cell
Multi-cellular organisms are
made of many cells
• Multi-cellular organisms exhibit a
hierarchy of cellular organization.
They are complex in that there is a
division of labor among the levels
of this hierarchy for carrying out
necessary life processes.
Cells perform numerous functions and
processes including respiration, waste
removal, growth, irritability, and
reproduction
Cells strive to maintain
equilibrium
• Osmosis is the passive transport
of water molecules across a cell
membrane. Diffusion is the
passive transport of substances
other than water across a cell
membrane. Cell membranes are
selectively permeable to various
substances.
Binomial nomenclature is the system
used for classifying organisms
• Kingdoms are
arranged using
system of names
recognizable
around the world
Division into Kingdoms is
based on:
• Information about physical
features and activities is arranged
in a hierarchy of increasing
specificity. The levels in the
accepted hierarchy include
domain, kingdom, phylum, class,
order, family, genus and species.
Current classification systems now generally
recognize the categorization of organisms into three
domains, Archaea, Bacteria and Eukarya.
• Any grouping of organisms into domains or
kingdoms is based on several factors,
including the presence or absence of cellular
structures, such as the nucleus, mitochondria,
or a cell wall; whether the organisms exist as
single cells or are multicellular; and how the
organisms get their food. For example, simple,
single-celled organisms that are able to
survive in extreme environments are believed
to be fundamentally different from other
organisms and may be classified in their own
domain (Archaea). Four different kingdoms of
the Eukarya domain of organisms are
generally recognized by scientists today
(Protista, Fungi, Plants, and Animals).
Moneran Kingdom
•
•
•
•
Unicellular, prokaryotic cells
No nucleus
All have a cell wall
Monerans are classified into two groups,
autotrophs, and heterotrophs.
• Or bacteria and cyanobacteria
• Or Eubacteria or Archaebacteria
Protista Kingdom
• Unicellular or multicellular, eukaryotic
• nucleus
• membrane
• form colonies or chains
• absorbs, ingests or
photosynthesize food
Fungi Kingdom
• Multi-cellular eukaryotic organisms
• Parasitic or saprophytic
• Reproduce using spores
Plants Kingdom
• Multi-cellular eukaryotes
• Producers, cells contain
chlorophyll
• Divided into nonvascular and vascular
• Four important plant
groups are the mosses,
ferns, conifers, and
flowering plants.
Animal Kingdom
• Divided into nonvertebrates and
vertebrates
• Eukaryotic cells
• Some important animal
groups (phyla) are the
cnidarians, mollusks,
annelids, arthropods,
echinoderms, and
chordates.
Species
• A group of similar-looking
organisms that can interbreed
under natural conditions and
produce offspring that are capable
of reproduction defines a species.
Producers make their own food by
photosynthesis and are the beginning
of food chains
• Chlorophyll is a
chemical in
chloroplasts that
can absorb or
trap energy and
transform it into
chemical energy
called glucose

Photosynthesis is the necessary life process that
transforms light energy into chemical energy. It
involves a series of chemical reactions in which the
light energy is used to change raw materials (carbon
dioxide and water) into products (sugar and
oxygen). The energy is stored in the chemical bonds
of the glucose (sugar) molecules.
Plants perform cellular respiration as well as
photosynthesis.
Plants convert the sugars they produce into
other raw materials that are used by plants
and animals for growth, repair, and energy
needs.
• Energy is a basic need of all living
things. Photosynthesizing
organisms obtain their energy
from the sun. Plants and other
photosynthesizing organisms are
often called producers because of
their ability to produce glucose
(sugar).
Photosynthesizing
organisms are at the base
of the energy pyramid.
LS.6
• In order to understand how an
ecosystem functions, one must
understand the concept of a
system and be able to envision
models of systems.
The four parts of the water
cycle are evaporation,
condensation,
precipitation, and
collection (infiltration).
In the carbon dioxide oxygen
cycle, producers release
oxygen for consumers
who release carbon
dioxide for the producers.
Nitrogen cycle is the circular path in
which nitrogen moves through
the environment. Nitrogen is a
gas that makes up 78% of the
earth’s atmosphere.
Nitrates are a combination of oxygen and
nitrogen, absorbed by the roots of plants
Nitrifying bacteria converts ammonia
from dead plants and animals and animal
waste to nitrates that can be used by plants
Denitrifying bacteria converts ammonia from
dead plants and animals and animal waste.
Nitrogen, which is released into the atmosphere
Nitrogen converters combine oxygen and
nitrogen to make nitrates. Ex. Lighting,
bacteria in the soil, algae in wet areas
Ammonia is a gas given off by dead plants and animals waste
A pyramid shows relative
amounts of energy available
to each level.
Omnivores are animals that eat animals and
plants.
Herbivores are animals that eat only
plants.
Carnivores are animals that eat only
meat.
• The amount of energy available to
each successive trophic level
(producer, first-order consumer,
second-order consumer, thirdorder consumer) decreases. This
can be modeled through an energy
pyramid, in which the producers
provide the broad base that
supports the other interactions in
the system.
•
•
•
1st level consumer-Primary consumer
usually herbivores, animals that eat
plants and algae.
2nd level consumers- Secondary
consumers usually carnivores, animals
that eat the primary producers.
3rd level consumers- Tertiary
consumer’s animals that don’t have
predators, they are considered the top
of the food chain.
Food Chain
• A food chain is a diagram of
relationships between living
organisms. Shows living things
depend on other things to live.
Animals eat other animals to
survive. A complex balance of
life. If one animal’s source of
food disappears, other animals
may be impacted and die.
A food web is two or more
food chains hooked together
You are getting there!!!!
• Almost as smart
as a seventh
grader!!!!!