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Mrs. Padilla- 7th Grade Life Science
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Science Notes

 

Looking Inside Cells

Chapter 1, Section 3

Pages 34-42

 

Make sure you know the following vocabulary:
  1. organelle
  2. cell wall
  3. cell membrane
  4. nucleus
  5. chromatin
  6. nucleolus
  7. cytoplasm
  8. mitochondria
  9. endoplasmic reticulum
  10. ribosomes
  11. Golgi bodies
  12. chloroplasts
  13. vacuole
  14. lysosome
  15. prokaryote
  16. eukaryote


Introduction (pages 34-35)

  • Organelles- tiny cell structures that carry out specific functions within the cell

Cell Wall (page 35)

  • A rigid layer of material surrounding plant cells and some bacterial cells
  • Stiffness allows plants to grow very tall, but still allows water and nutrients to pass through 

Cell membrane (pages 35-36)

  • All cells have cell membranes
  • In cells without cell walls, this is the outer layer
  • Controls what goes in and out of the cell

Nucleus (pages 36-37)

  • The “brain” of the cell

Nuclear Membrane (page 36)

  • Surrounds the nucleus
  • Controls what goes in and out of the nucleus

      Chromatin (page 37)

  • Strands of genetic material
  • Directs the functions of the cell

Nucleolus (page 37)

  • Structure within the nucleus that makes ribosomes

Organelles in the Cytoplasm (pages 37-41)

  • Cytoplasm is a thick, clear, gel-like fluid
  • Cytoplasm is in constant motion to transport materials 

Mitochondria (page 37)

  • The “power-house” of the cell which produces energy needed by the cell

Endoplasmic Reticulum (page 40)

  • Passageways that carry proteins from the ribosomes to the Golgi bodies

Ribosomes (page 40)

  • Found on the outer surface of the endoplasmic reticulum and in the cytoplasm
  • Produce proteins

Golgi Bodies (page 40)

  • Flattened sacs and tubes
  • Receive proteins from the endoplasmic reticulum, package them and pass them to the rest of the cell
  • Also release materials to the outside of the cell

Chloroplasts (page 40)

  • Found only in plant cells and some unicellular organisms
  • Capture energy from the sun and use it to produce food for the cell

Vacuoles (page 41)

  • The storage area of the cell for food, water or waste
  • In plant cells, vacuoles often contain water, making the cell plump

Lysosomes (page 41)

  • Small, round sacs that contain chemicals to break large food particles into smaller ones
  • The lysosome’s membrane keeps the chemicals inside so the rest of the cell doesn’t get dissolved

Bacterial Cells (page 41)

  • Bacterial cells have:
    • cell wall
    • cell membrane
    • ribosomes
    • genetic material that floats in the cytoplasm
  • Bacterial cells do not have a nucleus
  • Prokaryote- a cell without a nucleus
  • Eukaryote- a cell with a nucleus

Specialized Cells (page 42)

  • In multi-cellular organisms, cells are specialized
  • Specialized cells carry out different functions (ex. bone cells vs. blood cells)
  • Red blood cells, made in the bone marrow, carry oxygen to the cells
  • White blood cells, also made in the bone marrow, fight diseases.
  • Neurons, or nerve cells, carry messages though out the body.

Body Systems

Organ system

Major parts

Functions

Interactions with other organ systems

Muscular system

·      Skeletal muscles

·      Smooth muscles

·      Cardiac muscles

·      Motion

·      Heart beat

·      Breathing

·      Churning food in stomach

 

·      Works with other muscles to contract and relax

 

Skeletal system

·      Bones

·      joints

·      cartilage

·      ligaments

·      Shape and support

·      Motion

·      Protection

·      Produces blood cells

·      Stores material

·      Works with muscles to move

 

 

Integument system (skin)

·      Epidermis

·      Dermis

 

·      Covers body

·      Prevents water loss

·      Prevents injury and infection

·      Regulates body temperature

·      Eliminates waste produces vitamin D

·      Gathers information about the surroundings

·      Works with nervous system to gather information about surroundings

·      Works with blood to control temperature

Digestive system

·      Mouth

·      Esophagus

·      Stomach

·      Small intestine

·      Liver

·      pancreas

·      Large intestine

·      Rectum

·      Anus

·      Breaks food into useable molecules

·      Allows  molecules to be absorbed into the blood stream

·      Eliminates waste

·      Works with the muscular system which helps move materials through

·      Works with the blood system which absorbs nutrients from the digestive tract

Cardiovascular (circulatory) system

·      Heart

·      Blood

·      Blood vessels (arteries, veins, capillaries)

·      Moves nutrients through the body Moves gases (oxygen and carbon dioxide) through the body

·      Fights infections and diseases

·      Removes waste materials

 

·      Works with digestive system to absorb nutrients

·      Works with respiration system to carry oxygen and carbon dioxide

 

Respiratory system

·      Nose

·      Pharynx

·      Trachea

·      lungs

·      Takes in oxygen, removes carbon dioxide

·      Circulatory system carries gases to and from the respiratory system

·      Muscular system allows for inhaling and exhaling

 

 

Excretory system

·      Kidneys

·      Lungs

·      Skin

·      liver

·      Filters wastes out of the blood

·      Takes waste out of the blood stream

Nervous system

·      Neurons

·      Central nervous system

o       Brain

o       spinal cord

·      Peripheral nervous system

·      Senses (eyes, ears, nose, tongue)

·      Monitors what is happening inside the body

·      Monitors what is happening outside the body

·      Responds to changes in surroundings

 

 


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