1) Homeostasis, Cell Biology, Microbiology

Question 1

Name 8 human function characteristics

Answer 1

maintaining boundaries; movement; responsiveness; digestion; metabolism; excretion; reproduction; growth

Question 2

Name 5 human survival needs

Answer 2

nutrients; oxygen; water; normal body temperature (37 degrees C); appropriate atmospheric pressure

Question 3

Define homeostasis

Answer 3

maintaining a constant/stable internal environment despite external conditions

Question 4

Name 3 key components of homeostatic regulation

Answer 4

receptors; control centre; effector

Question 5

What is the role of a receptor within a homeostatic control mechanism?

Answer 5

responds to stimuli; informs control centre; via the afferent pathway

Question 6

What is the role of the control centre within a homeostatic control mechanism?

Answer 6

determines set point; analyses information; determines appropriate response

Question 7

What is the role of an effector within a homeostatic control mechanism?

Answer 7

provides a means for response to the stimulus; receives information from control centre via efferent pathway

Question 8

Define negative feedback

Answer 8

feedback that causes the stimulus to decline or end

Question 9

Give 4 examples of negative feedback mechanisms

Answer 9

thermoregulation; regulation of blood pressure; hunger physiology; blood sugar (glucose homeostasis)

Question 10

Define positive feedback

Answer 10

feedback that tends to cause a variable to change in the same direction as the initial change; enhances the stimulus

Question 11

Give 5 examples of positive feedback mechanisms

Answer 11

blood clotting; childbirth; breast feeding; menstrual cycle; nerve signalling

Question 12

Name the 3 main regions of the cell

Answer 12

nucleus; plasma membrane; cytoplasm

Question 13

Describe the nucleus

Answer 13

control centre of the cell; responsible for transmitting genetic information and providing the instructions for protein synthesis

Question 14

Function of nuclear envelope?

Answer 14

separates the nucleoplasm from the cytoplasm and regulates passage of substances to and from the nucleus

Question 15

Function of nucleolus?

Answer 15

site of ribosome subunit manufacture

Question 16

Function of chromatin?

Answer 16

DNA constitutes the genes, which carry instructions for building proteins

Question 17

Describe the cytoplasm

Answer 17

cellular region between the nuclear and plasma membranes; consists of fluid cytosol containing dissolved solutes, organelles and inclusions

Question 18

What are inclusions?

Answer 18

stored nutrients, secretory products, pigment granules

Question 19

Function of mitochondria?

Answer 19

site of aerobic respiration and ATP synthesis

Question 20

Function of ribosomes?

Answer 20

sites of protein synthesis

Question 21

Function of rough endoplasmic reticulum?

Answer 21

sugar groups are attached to proteins within the tunnels; proteins are bound in vesicles for transport to Golgi apparatus and other sites; external face synthesises phospholipids

Question 22

Function of smooth endoplasmic reticulum?

Answer 22

site of lipid and steroid (cholesterol) synthesis, lipid metabolism and drug detoxification

Question 23

Function of Golgi apparatus?

Answer 23

packages, modifies and segregates proteins for secretion from the cell, inclusion in lysosomes, or incorporation into the plasma membrane

Question 24

Function of peroxisomes?

Answer 24

enzymes (oxidase and catalase) detoxify a number of toxic substances e.g. free radicals

Question 25

What substance does catalase break down?

Answer 25

hydrogen peroxide

Question 26

Function of lysosomes?

Answer 26

sites of intracellular digestion

Question 27

Function of microtubules?

Answer 27

supports cell and gives it shape; involved in intracellular and cellular movements; forms centrioles, cilia and flagella, if present

Question 28

Function of microfilaments?

Answer 28

involved in muscle contraction and other types of intracellular movement; help form the cell cytoskeleton and microvilli, if present

Question 29

Function of intermediate filaments?

Answer 29

stable cytoskeleton elements; resist mechanical forces acting on the cell

Question 30

Function of centrioles?

Answer 30

organise a microtubule network during mitosis (cell division) to form the spindle and asters; form the basis of cilia and flagella

Question 31

Function of inclusions?

Answer 31

storage for nutrients, wastes and cell products

Question 32

Describe the plasma membrane

Answer 32

membrane made of a double layer of lipids with proteins embedded within

Question 33

Function of plasma membrane?

Answer 33

serves as an external cell barrier and acts in transport of substances into or out of the cell. Maintains an electrical condition that is essential for functioning of excitable cells. Externally facing proteins acts as receptors, transport proteins and in cell-to-cell recognition

Question 34

Define diffusion

Answer 34

movement of molecules from an area of higher to lower concentration across a semipermeable membrane until equilibrium is achieved

Question 35

Define filtration

Answer 35

passage of a solvent and dissolved substances through a membrane or filter

Question 36

Define osmosis

Answer 36

the diffusion of a solvent through a membrane from a dilute solution into a more concentrated one

Question 37

Describe active transport

Answer 37

transport of substances up their concentration gradient, requiring energy

Question 38

Define exocytosis

Answer 38

movement out of a cell

Question 39

Define endocytosis

Answer 39

movement into a cell

Question 40

Define phagocytosis

Answer 40

the ingestion of solid particles by cells

Question 41

Define pinocytosis

Answer 41

the engulfing of extracellular fluid by cells

Question 42

Define isotonic and its cell reactions

Answer 42

uniform tension; of the same tone | at equilibrium so no net movement

Question 43

Define hypertonic and its cell reactions

Answer 43

excessive, above normal tone or tension | fluid moves out of RBC

Question 44

Define hypotonic and its cell reactions

Answer 44

below normal tone or tension | fluid moves into RBC

Question 45

What are the two key parts of the cell cycle?

Answer 45

Interphase and mitotic phase

Question 46

What occurs during interphase?

Answer 46

normal cell activities, G1, S and G2