• Proteins are made of Amino
Acid chains
• Amino acids are linked in a sequence

Ribosomes
• Proteins are bonded together at the ribosomes
• # 2 on diagram

• Order of amino acid chain determines a proteins shape
• Shape determines its function

• Receptor molecules
• Nerve chemicals
• Hormones
• Enzymes
Proteins have shapes

• Located on surface of membrane to receive signals from nerve chemicals or hormones
1 2 3

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3-D view of receptor molecules
• What kind of molecules are receptors?
• Proteins

•

Receptor molecules are Proteins
• They have a specific shape
• Signals they receive must have a shape that can fit into them
Receptor Signal

Primary Agents to Communicate
Receptor molecule
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•

• Another pictorial example of a receptor molecule and a hormone

• Signals released by glands so cell can communicate with
• Hormone has to fit on receptor molecule of the target cell

Amino acid molecules are bonded together in a specific sequence on cell structures known as
1.ribosomes
2.vacuoles
3.mitochondria
4.centromeres

The shape of a protein is most directly determined by the
1.amount of energy available for synthesis of the protein
2.kind and sequence of amino acids in the protein
3.type and number of DNA molecules in a cell
4.mistakes made when the DNA is copied

A characteristic shared by all enzymes, hormones, and antibodies is that their function is determined by the
1.shape of their molecules
2.DNA they contain
3.inorganic molecules they contain
4.organelles present in their structure

Nerve cells are essential to an animal because they directly provide
1.communication between cells
2.transport of nutrients to various organs
3.regulation of reproductive rates within other cells
4.an exchange of gases within the body

Which substances are found on cell surfaces and respond to nerve and hormone signals?
1.starches and simple sugars
2.subunits of DNA
3.vitamins and minerals
4.receptor molecules

Letter B indicates a
1.ribosomes
2.receptor molecules
3.tissues
4.inorganic substances

Base your answer on the diagram and on your knowledge of biology.
Which statement best describes the diagram?
1.Nerve cell X is releasing receptor molecules.
2.Nerve cell Y is signaling nerve cell X .
3.Nerve cell X is attaching to nerve cell Y .
4.Nerve cell Y contains receptor molecules for substance A

Cellular communication is illustrated in the diagram below
.
Information can be sent from
1.cell A to cell B because cell B is able to recognize signal 1
2.cell A to cell B because cell A is able to recognize signal 2
3.cell B to cell A because cell A is able to recognize signal 1
4.cell B to cell A because cell B is able to recognize signal 2