7th Grade End of the Year Final Review
Cells
Cell theory:
- All living things are made of cells.
- Cells are the basic unit of structure & function in living things.
- All cells come from pre-existing cells.
Cell organelles:
- Nucleus-control center of the cell
- Chloroplasts-traps energy from sunlight and uses it to make food
- Cell wall-gives plant cells their rigid, boxlike shape; support & protect
- Cell membrane-controls movement of materials in & out of cell
- Cytoplasm-jelly-like substance that supports & protects cell organelles
- Mitochondrion-breaks down sugar (glucose) to produce energy; “powerhouse”
- Vacuole-stores food, water & wastes
Know the differences between plant & animal cells. Plants cells have a cell wall & chloroplasts but animal cells do not. Animal cells have lysosomes which are rarely found in plant cells.
Organic Compounds
All organic compounds contain carbon and other elements such as hydrogen, nitrogen, oxygen, phosphorus, or sulfur. CHNOPS
Chromosome Theory of Inheritance
The chromosome theory of inheritance says that genes are carried from parents to offspring on chromosomes.
Sexual & Asexual Reproduction
Sexual reproduction-involves 2 parents (egg & sperm) & produces genetically diverse offspring (has a better chance of surviving changes in the environment)
Asexual reproduction-involves 1 parent & produces genetically identical offspring (ex. budding, fragmentation, cell division, self pollination)
Body Systems
Know the main functions of each body system and how they work together.
Circulatory system-transports oxygen, nutrients & wastes
Respiratory system-brings in oxygen, removes carbon dioxide
Nervous system-carries messages back & forth between the brain & other parts of the body
Muscular system
Skeletal system
Digestive system
Excretory system
Reproductive system
Integumentary system
Endocrine system
Chemical & Mechanical Digestion
Mechanical digestion-the physical breaking apart of food; a physical change (ex. chewing, churning of stomach)
Chemical digestion-when food is broken down into a new substance; causes a chemical change (ex. enzymes, digestive juices)
Biodiversity
Biodiversity refers to the number of different species in an ecosystem.
Biodiversity contributes to the sustainability of an ecosystem. With less biodiverisity, the extinction of a species greatly affects an ecosystem.
An ecological benefit to biodiversity is that the ecosystem remains more stable.
Natural Selection
Darwin observed that the beaks of finches in the Galapagos Islands were adaptations related to the foods the finches ate.
Natural selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce.
Selective breeding is when humans bred animals or plants to get desired characteristics.
Succession
Primary succession steps- no soil or life-- lichens & mosses grow--soil forms--weeds & grasses grow--trees & shrubs grow
Secondary succession is the series of changes that occur when an ecosystem has been disturbed but soil and organisms still exist.
Ecosystems
An autotroph is an organism that can make its own food.
A producer is an organism that can make its own food.
An omnivore is a consumer that eats both plants and animals.
1st level consumers eat only producers.
Be able to understand food webs and energy pyramids.
Dichotomous Keys
Be able to read and follow a dichotomous key.
Groundwater & Surface Water
Pollution that gets into groundwater is difficult to remove and can travel far distances from the point of pollution.
Causes of surface water pollution:
Chemical wastes, metal wastes, animal wastes, pesticides, fertilizer, sediments, heat, oil & gasoline
Causes of groundwater pollution:
Chemical wastes, metal wastes, human wastes, water wastes, pesticides, fertilizer, oil & gasoline
Work
In science, in order for work to be done on an object, the force exerted must be in the same direction as the object’s motion.
Be able to identify examples of work being done.