Transcript Science 8 Review

KEY IDEAS: VIRUSES
1. viruses are considered to be nonliving because viruses
are not cells, and they do not use energy to grow and
develop, or to respond to their surroundings.
2. all viruses have two basic parts: an outer coat that
protects the virus and an inner core made of genetic
material.
3. once inside a cell, a virus uses the host cells’ functions
to make its own proteins and genetic material. The
proteins and genetic material assemble into new viruses.
Which burst destroying the host.
KEY IDEAS: BACTERIA
1. Bacteria are prokaryotes. Their cells do not have nuclei that
contain the cell’s genetic material. Instead, the genetic
material floats freely in the cytoplasm.
2. Bacteria reproduce asexually by binary fission, which results
in the production of two cells exactly like the parent cell.
Some bacteria have a simple form of sexual reproduction
called conjugation. This process results in a cell with a new
combination of genetic information.
3. Bacteria play positive roles in the lives of humans. Bacteria
are involved in fuel and food production, in environmental
recycling and cleanup, and in the production of medicines.
VIRUSES, BACTERIA AND YOUR HEALTH
1. Infectious disease can spread through contact with
an infected person, a contaminated object, an
infected animal, or an environmental source.
2. There is no cure for viral disease. Bacterial disease
can be cured through the use of antibiotics.
Vaccines can prevent some viral and bacterial
diseases.
KEY IDEAS: PROTISTS
1. Animal-like protists, or protozoans, include sarcodines,
ciliates, zooflagellates, and sporozoans. Like animals, these
protists are heterotrophs. Most protozoans move by using
pseudopods, cilia, or flagella.
2. Fungus like protists include water molds, downy mildews,
and slime molds. Like fungi, these protists are heterotrophs,
have cell walls, and use spores to reproduce.
3. Plantlike protists, or algae, include euglenoids,
dinoflagellates, diatoms, green algae, red algae, and brown
algae. Like plants, these organisms are autotrophs.
KEY IDEAS: ALGAL BLOOMS
1. Red tides occur when a population of algae
increases quickly in ocean waters. Some algae can
secrete toxins that poison animals.
2. Nutrients in a lake or pond build up over time,
causing an increase in the numbers of algae. An
accelerated rate of eutrophication can lead to the
deaths of many organisms in the lake or pond.
KEY IDEAS: FUNGI
1. Most fungi are eukaryotes, use spores to reproduce, and
are heterotrophs.
2. Most fungi feed by absorbing food through their hyphae.
The hyphae secrete digestive chemicals into a food
source, which is broken down into small substances that
are absorbed by the hyphae.
3. Fungi produce spores in structures called fruiting bodies.
The majority of fungi reproduce both asexually and
sexually.
4. Fungi are decomposers that recycle Earth’s chemicals. In
addition, some fungi cause disease while some fight
disease. Many produce important foods for people. Some
fungi live in symbiotic relationships with other organisms.
KEY IDEAS: THE PLANT KINGDOM
1. Plants are autotrophs. All plants are also multicellular
eukaryotes.
2. Plants cells have cell walls that are made mostly of
cellulose. Plants cells contain chloroplasts, in which food is
made, and vacuoles that store water, food, and other
substances.
3. All plants have complex life cycles. In the sporophyte
stage, plants produce spores. In the gametophyte stage,
plants produce sperm cells and egg cells.
4. For plants to survive on land, they need ways to obtain
water and other materials from their surroundings, retain
moisture, support their bodies, transport materials
throughout the pant, and reproduce successfully.
KEY IDEAS: PHOTOSYNTHESIS AND
LIGHT
1. White light is made up of the different colors of
the rainbow-red, orange, yellow, green, blue,
and violet.
2. Most of the light that strikes a leaf is absorbed
by pigments in the chloroplasts of the cells.
Chlorophyll, the main pigment, absorbs red and
blue light. Light energy powers the process of
photosynthesis.
3. In photosynthesis, carbon dioxide and water are
converted into sugars and oxygen using the light
energy.
KEY IDEAS: MOSSES, LIVERWORTS,
AND HORNWORTS
1. Nonvascular plants are small, low-growing
plants that lack vascular tissue. Most
nonvascular plants transport materials by
passing them from one cell to the next. They
live in areas where they are enough moisture
for them to survive.
2. Mosses, liverworts, and hornworts are three
types of nonvascular plants.
KEY IDEAS: FERNS AND THEIR
RELATIVES
1. Seedless vascular plants have vascular tissue
and sue spores to reproduce. These plants
include ferns, club mosses, and horsetails.
2. Although seedless vascular plants grow taller
than nonvascular plants, they still need to
live in moist places. The plants’s spores are
released into the environment, where they
grow into gametophyte.