3A CELL STRUCTURE

Question 1

cytoplasm

Answer 1

a jelly-like liquid that makes up the bulk of the cell and contains the organelles

Question 2

nucleus

Answer 2

an organelle containing the nucleic acids DNA and RNA, as well as protein, surrounded by a double nuclear membrane with pores

Question 3

protoplasm

Answer 3

the cytoplasm and nucleus combined

Question 4

ultrastructure

Answer 4

the detailed organisation of the cell, only visible using the electron microscope

Question 5

intracellular

Answer 5

inside the cell

Question 6

chromatin

Answer 6

the granular combination of DNA bonded to protein found in the nucleus when the cell is not actively dividing

Question 7

nucleolus

Answer 7

an extra-dense region of almost pure DNA and protein found in the nucleus; it is involved in the production of ribosomes and control of growth and division

Question 8

mitochondria

Answer 8

rod-like structures with inner and outer membranes that are the site of aerobic respiration

Question 9

cristae

Answer 9

the infoldings of the inner membrane of the mitochondria which provide a large surface area for the reactions of aerobic respiration

Question 10

eubacteria

Answer 10

true bacteria (prokaryotic organisms)

Question 11

centrioles

Answer 11

bundles of tubules found near the nucleus and involved in cell division by the production of a spindle of microtubules that move the chromosomes to the ends of the cell

Question 12

80S ribosomes

Answer 12

the main type of ribosome found in eukaryotic cells, consisting of ribosomal RNA and protein, made up of a 60S and a 40S subunit; they are the site of protein synthesis

Question 12

spindle

Answer 12

a set of overlapping protein microtubules running the length of the cell, formed as the centrioles pull apart in mitosis and meiosis

Question 13

70S ribosomes

Answer 13

the ribosomes found in the mitochondria and chloroplasts of eukaryotic cells and in prokaryotic organisms

Question 14

endosymbiotic theory

Answer 14

a theory that suggests mitochondria and chloroplasts originated as independent prokaryotic organisms that began living symbiotically inside other cells as endosymbionts

Question 15

lysosomes

Answer 15

organelles full of digestive enzymes used to break down worn-out cells or organelles or digest food in simple organisms

Question 16

apoptosis (programmed cell death)

Answer 16

the breakdown of worn-out, damaged or diseased cells by the lysosomes

Question 17

endoplasmic reticulum ER

Answer 17

a 3D network of membrane-bound cavities in the cytoplasm that links to the nuclear membrane and makes up a large part of the cellular transport system as well as playing an important role in the synthesis of many different chemical substances

Question 18

rough endoplasmic reticulum RER

Answer 18

endoplasmic reticulum that is covered in 80S ribosomes and which is involved in the production and transport of proteins

Question 19

exocytosis

Answer 19

the movement of large molecules out of cells by the fusing of a vesicle containing the molecules with the surface cell membrane; the process requires ATP

Question 20

smooth endoplasmic reticulum SER

Answer 20

a smooth tubular structure similar to RER, but without the ribosomes, which is involved int he synthesis and transport of steroids and lipids in the cell

Question 21

Golgi apparatus

Answer 21

stacks of membranes that modify proteins made elsewhere in the cell and package them into vesicles for transport, and also produce materials for plant cell walls and insect cuticles

Question 22

peptidoglycan

Answer 22

a large, net-like molecule found in al bacterial cell walls made up of many parallel polysaccharide chains with short peptide cross-linkages

Question 23

capsule

Answer 23

a layer formed form starch, gelatine, protein or glycolipid, found around the outside of some bacteria

Question 24

bacteriophage

Answer 24

virus that attacks bacteria

Question 24

pili

Answer 24

thread-like protein projections found on the surface of some bacteria

Question 25

flagella

Answer 25

many-stranded helices of the contractile protein flagellin found on some bacteria; they move the bacteria by rapid rotations

Question 26

plasmids

Answer 26

small, circular pieces of DNA that code for specific aspects of the bacterial phenotype

Question 27

mesosomes

Answer 27

infoldings of the cell membrane of bacteria

Question 28

Gram staining

Answer 28

a staining technique used to distinguish types of bacteria by their cell wall

Question 28

gram-positive bacteria

Answer 28

bacteria that contain teichoic acid in their cell walls and stain purple/blue with Gramm staining

Question 29

Gram-negative bacteria

Answer 29

bacteria that have no teichoid acid in their cell walls; they stain red with Gram staining

Question 29

teichoic acid

Answer 29

a chemical substance found in the cell walls of Gramm-positive bacteria

Question 30

cocci

Answer 30

spherical bacteria

Question 31

bacilli

Answer 31

rod-shaped bacteria

Question 32

spirilla

Answer 32

bacteria with twisted or spiral shape

Question 33

vibrios

Answer 33

comma-shaped bacteria

Question 34

obligate aerobes

Answer 34

organisms that need oxygen for respiration

Question 35

facultative anaerobes

Answer 35

organisms that use oxygen if it is available, but can respire and survive without it

Question 36

obligate anaerobes

Answer 36

organisms that can only respire in the absence of oxygen and are killed by oxygen

Question 37

tissues

Answer 37

groups of specialised cells carrying out particular functions in the body

Question 38

organs

Answer 38

structures made up of several different types of tissue to carry out particular functions in the body

Question 39

epithelial tissues

Answer 39

tissues that form the lining of surfaces inside and outside the body

Question 40

organ system

Answer 40

a group of organs working together to carry out particular large-scale functions in the body