Chapter 3-Cells

Question 1

Cell

Answer 1

the smallest unit of life. Cells are the building blocks of living things. There are many different sized and shaped cells in animals and plants, as well as single-celled organisms.

Question 2

Light Microscope

Answer 2

instrument for viewing very small objects. A light microscope can magnify things up to 1500 times.

Question 3

Scanning Electron Microscope

Answer 3

an electron microscope in which the surface of a specimen is scanned by a beam of electrons that are reflected to form an image.

Question 4

Unicellular

Answer 4

describes an organism having only one cell

Question 5

Multicellular

Answer 5

having many cells. Most plants and animals are multicellular.

Question 6

Micrometre

Answer 6

a length of one millionth of a metre

Question 7

Nanometre

Answer 7

a unit of measurement equal to one billionth of a metre

Question 8

Eukaryotes

Answer 8

member of the group of organisms that has a membrane around the nucleus in each of their cells

Question 9

Prokaryotes

Answer 9

organism classified as belonging to the Prokaryotae kingdom, the kingdom of organisms that consist of single cells with a nucleus not surrounded by a membrane or a cell wall, commonly called bacteria

Question 10

Cell Membrane

Answer 10

structure that encloses the contents of a cell and allows the movement of some materials in and out

Question 11

Nucleus

Answer 11

roundish structure inside a cell that acts as the control centre for the cell. Plural = nuclei.

Question 12

Cytosol

Answer 12

the fluid found inside cells

Question 13

Ribosomes

Answer 13

small structures within a cell in which proteins such as enzymes are made

Question 14

Cytoplasm

Answer 14

the jelly-like material inside a cell. It contains many organelles such as the nucleus and vacuoles.

Question 15

Chloroplasts

Answer 15

oval-shaped organelle found only in plant cells. Chloroplasts contain the pigment chlorophyll. They are the ‘factories’ in which carbon dioxide and water are changed by sunlight and water into food by the process of photosynthesis.

Question 16

Chlorophyll

Answer 16

the green-coloured chemical in plants that absorbs the light energy used in photosynthesis to make food from carbon dioxide and water

Question 17

Photosynthesis

Answer 17

the food-making process in plants that takes place in chloroplasts within cells. The process uses carbon dioxide, water and energy from the sun.

Question 18

Guard Cells

Answer 18

cells on either side of a stoma that work together to control the opening and closing of the stoma

Question 19

Stomata

Answer 19

small openings mainly on the lower surface of leaves. These pores are opened and closed by guard cells. Singular = stoma.

Question 20

Xylem Cells

Answer 20

pipelines for the flow of water up plants. They are made up of the remains of dead xylem cells fitted end to end with the joining walls broken down. Lignin in the cell walls gives them strength.

Question 21

Phloem Cells

Answer 21

Cells that make up a type of tissue that transports sugars made in the leaves to other parts of a plant

Question 22

Translocation

Answer 22

transport of materials, such as water and glucose, in plants

Question 23

Mitosis

Answer 23

cell division process that results in new cells with the same number of chromosomes as the original cell

Question 24

Chromosomes

Answer 24

tiny, thread-like structure inside the nucleus of a cell. Chromosomes contain the DNA that carries genetic information.

Question 25

DNA

Answer 25

deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

Question 26

Cytokinesis

Answer 26

the process where the cytoplasm of a cell divides to form two daughter cells

Question 27

Antiseptic

Answer 27

mild disinfectant used on body tissue to kill microbes

Question 28

Disinfectant

Answer 28

chemical used to kill bacteria on surfaces and non-living objects

Question 29

Antibiotics

Answer 29

substance derived from a micro-organism and used to kill bacteria in the body

Question 30

Epidermis

Answer 30

outermost layer of the skin