Cell Membrane and Feedback

Question 1

Functions of a Cell Membrane

Answer 1

1. Selectively Permeable or Semipermeable
2. Separate inside cytoplasm from extracellular (outside) environment
   3.Receives chemical messengers (hormones, neurotransmitters, medicines) & passes the info to
   the cell so it can respond.

Question 2

Phospholipids Bilayer

Answer 2

Determines what
molecules can enter &
leave the cell based on
their charge & size.

Question 3

Cholesterol

Answer 3

Located b/w the fatty
acids to stabilize &
strengthen the flexible cell
membrane.

Question 4

Anchor
Proteins

Answer 4

Keep cells attached forming tissues.

Question 5

Identifier (Cell
Recognition) Proteins

Answer 5

Helps immune system
distinguish “self” vs.
foreign.
▪ Have unique carbohydrate
chains attached!

Question 6

Enzymatic
Proteins

Answer 6

Catalyze METABOLIC reactions.

• Active site exposed to
  substances in cytoplasm.

Question 7

Receptor Proteins

Answer 7

Receive chemical messengers & pass the info to the cell so it can RESPOND!

Question 8

Target Cells

Answer 8

Have specifically shaped receptor proteins for only certain chemical messengers.

Question 9

Hormones &
Neurotransmitters

Answer 9

Types of chemical messengers that bind to specific receptors in order to transmit a message.

Question 10

Channel Proteins

Answer 10

Provides a hydrophilic channel so charged substances can cross the
membrane.

Question 11

Carrier Proteins

Answer 11

Change shape while shuttling SPECIFICALLY SHAPED substances
across the membrane.

Question 12

Endocrine System

Answer 12

Contains glands that secrete
hormones (chemical messengers) into the bloodstream.

Question 13

Feedback Mechanism

Answer 13

Maintains a living system’s
internal conditions within
certain limits and mediates
behaviors, allowing it to
remain alive and functional
even as external conditions
change within some range.

Ex. Positive feedback &
Negative Feedback

Question 14

Positive Feedback

Answer 14

Amplifies the initial stimuli
by moving the system
away from its starting state
to achieve a goal.

Ex. childbirth, blood clotting,
and ripening of fruit

Question 15

Negative Feedback System

Answer 15

Mechanism that counteracts a
disruption in homeostasis to
reestablish internal stability

Question 16

Insulin

Answer 16

Hormone that helps decrease blood glucose
levels.

Question 17

Glucagon

Answer 17

Hormone that helps increase blood
glucose levels.

Question 18

Pancreas

Answer 18

Organ that secretes insulin or glucagon from specialized cells into the bloodstream by exocytosis.

Question 19

Liver

Answer 19

Organ that stores glucose as glycogen (polysaccharide)

Question 20

Glycogen

Answer 20

Polysaccharide (made of MANY glucose molecules bonded together by dehydration synthesis)

Question 21

Diabetes

Answer 21

Metabolic disease that causes HIGH blood glucose levels (hyperglycemia)