cell membrane and feedback Flashcards
Positive feedback system
amplifies the initial stimuli by moving the system away from it’s starting state to achieve a goal
Examples of positive feedback
Childbirth, blood clotting, ripening of fruit
negative feedback system
Mechanism that counteracts a disruption in homeostasis to reestablish internal stability
Examples of negative feedback
temperature control, calcium regulation, blood glucose (sugar) regulation
Insulin
hormone that helps decrease blood glucose levels.
Glucagon
Hormone that helps increase blood gluclose levels
Pancreas
Organ that secretes insulin or glucagon from specialized cells into the bloodstream by exocytosis
Liver
organ that stores gluclose as glycogen (polysaccharide)
Glycogen
Polysaccharide that is made of many gluclose molecules bonded together by dehydration synthesis
HYPOglycemia sugar level
LOW sugar
Normal level sugar level
NORMAL sugar
HYPERglycemia sugar level
HIGH sugar
Diabetes
Metabolic disease that causes HIGH blood gluclose levels (hyperglycemia)
Type 1 diabetes
Insulin is not produced by beta cells in pancreas and hence gluclose is not removed from the bloodstream
Type 2 diabetes
Prolonged overproduction of insulin leads to desensitization of the insulin receptors and they get worn out leaving gluclose not removed from the blood stream
Hydrolosis
Process used when liver breaks down glycogen stores and releases gluclose to the blood.
Endocrine system
contains glands that secrete hormones (chemical messengers) into the bloodstream
Feedback Mechanism
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
Functions of plasma membrane Part 1
- regulates what enters/leaves the cell
- Selectively permeable
Functions of plasma membrane Part 2
- Separates inside cytoplasm from outside enviroment
2.recieves chemical messengers and passes info into the cell so it can respond
Cholesterol
Located between the fatty acids to stabilize and strengthens the flexible cell membrane
Anchor proteins
keep cells attached forming tissues
Identifier proteins
Helps immune system distinguish self vs foreign
Enzymatic Proteins
catalyzes metabolic reactions
Receptor proteins
receive chemical messengers and pass the info into the cell so it can respond
Target cell
have specifically shaped receptor proteins for only certain chemical messengers
Channel Proteins
Provides a hydrophilic channel for charged substances can cross the membrane.
Carrier proteins
changed shape while shutting specifically shaped substances across the membrane
