b2 definitions (scaling up)

Question 1

define alveoli

Answer 1

small air sacs in the lungs that serves as the gaseous exchange surface. they provide a large surface area for efficient exchange.

Question 2

define aorta

Answer 2

the main artery that takes oxygenated blood away from the heart to the body

Question 3

define atrium

Answer 3

the upper chamber of the heart that receives the blood from the veins

Question 4

define bone marrow

Answer 4

a human tissue that contains stem cells which can develop into red blood cells

Question 5

define thecell cycle

Answer 5

a series of events that take place in a cell in preparation for cell division

Question 6

define cell differentiation

Answer 6

the production of specialised cells allowing organisms to become more efficient

Question 7

define companion cells

Answer 7

the active cells of the phloem. they provide energy for the phloem to transport substances

Question 8

define cytokinesis

Answer 8

the 3rd stage of the cell cycle in which 2 identical diploid daughter cells are formed

Question 9

define embryonic stem cells

Answer 9

a type of stem cell found in very early embryos that can differentiate into any cell type

Question 10

define guard cells

Answer 10

cells that control the opening and closing of the stomata

Question 11

define hypertonic

Answer 11

the net movement of water out of the cell via osmosis

Question 12

define hypotonic

Answer 12

the net movement of water into the cell via osmosis

Question 13

define interphase

Answer 13

the first stage of he cell cycle in which cells grow, new proteins are synthesised and chromosomes are replicated

Question 14

define lignin

Answer 14

a material that lines the xylem vessels and provides strength and support

Question 15

define meristematic cell

Answer 15

a type of cell that can differentiate into any plant cell type

Question 16

define meristem tissue

Answer 16

a plant tissue that contains many undifferentiated cells

Question 17

define mitosis

Answer 17

a type of cell division that produced two identical diploid daughter cells from one parent cell. it is the second stage of the cell cycle and it is important for growth, development and the replacement of damaged cells

Question 18

define muscle cell

Answer 18

a specialised animal cell that contracts or relaxes causing muscle movement

Question 19

define phloem

Answer 19

a plant tissue that transports sugars from the source to the sink

Question 20

define plasma

Answer 20

a pale yellow liquid found in the blood that carries water, enzymes, salts, nutrients, proteins, urea and hormones

Question 21

define plasmolysis

Answer 21

the net movement of water out of a plant cell, causing the cell membrane to move away from the cell wall. this results in cell death.

Question 22

define potometer

Answer 22

a piece of capillary tube that is used to investigate the rate of transpiration. water loss from the surface of the leaf is measured by the distance that the air bubble travels over a certain period of time.

Question 23

define pulmonary artery

Answer 23

the main artery that carries deoxygenated blood away from the heart to the lungs

Question 24

define pulmonary vein

Answer 24

the main vein that carries oxygenated blood back to the heart from the lungs

Question 25

define root hair cells

Answer 25

specialised cells that provide a large surface area for the uptake of water and minerals from the soil

Question 26

define sieve tubes

Answer 26

plant cells that have no nuclei and are connected via the cytoplasms

Question 27

define the stomata

Answer 27

small pores in the epidermis of the leaves that facilitate gaseous exchange

Question 28

define translocation

Answer 28

the process of transporting sucrose around the plant

Question 29

define turgid

Answer 29

when the vacuole of a plant cell becomes swollen and enlarged with water

Question 30

define vena cava

Answer 30

the main vein that carries deoxygenated blood back to the heart from the body

Question 31

define ventricles

Answer 31

the lower chambers of the heart that receive blood from the atria and pump it to the arteries. the heart has two ventricles.

Question 32

define vili

Answer 32

small projections from the small intestine that increase the surface area for food absorption

Question 33

define water potential

Answer 33

a measure for the tendency of water to move from one area to another area. it is represented by the sign Ψ

Question 34

define the xylem

Answer 34

a specialised plant tissue that transports water and dissolved minerals from the roots to the leaves of the plant