Cellular structure and function Flashcards
Glossary of key terms (117 cards)
1
Q
Active boundary
A
a barrier that is constantly changing and responsive to the environment
2
Q
aerobic respiration
A
the breakdown of glucose to simple inorganic compounds in the presence of oxygen and with release of energy that is transferred to ATP
3
Q
adenosine triphosphate (ATP)
A
the common source of chemical energy for cells
4
Q
Animalia
A
a group of eukaryotic multicellular organisms whose cells lack a cell wall
5
Q
archaea
A
a group of prokaryotes that live in extreme environments; also known as extremophiles
6
Q
autophagy
A
breakdown by lysosomes of non-functioning cell organelles that are old and/or damaged and in need of turnover
7
Q
bacteria
A
a group of prokaryotes that can reproduce by binary fission
8
Q
Biomacromolecules
A
large biological polymers such as nucleic acids, proteins and carbohydrates
9
Q
bulk transport
A
the movement of material into a cell (endocytosis) or out of a cell (exocytosis)
10
Q
capsule
A
polysaccharide layer outside the cell membrane for protection
11
Q
carrier protein
A
protein that binds to a specific substance and facilitates its movement through the membrane
11
Q
cell
A
basic functional unit of all organisms
12
Q
cell theory
A
theory that all living things are made of cells
13
Q
cell wall
A
semi-rigid structure located outside the plasma membrane in the cells of plants, algae, fungi and bacteria
14
Q
cell (plasma) membrane
A
partially permeable boundary of a cell separating it from its physical surroundings; boundary controlling entry to and exit of substances from a cell
15
Q
cellular respiration
A
process of converting the chemical energy of food into a form usable by cells, typically ATP
16
Q
cellulose
A
complex carbohydrate composed of chains of glucose molecules; the main component of plant cell walls
17
Q
centrioles
A
a pair of small cylindrical organelles, used in spindle development in animal cells during cell division
18
Q
channel proteins
A
trans-membrane proteins involved in the transport of specific substances across a plasma membrane by facilitated diffusion
19
Q
chitin
A
a fibrous substance, mainly composed of polysaccharides, used in the cells walls of fungi
20
Q
chlorophyll
A
green pigment required for photosynthesis that traps the radiant energy of sunlight
21
Q
chloroplast
A
chlorophyll-containing organelle that occurs in the cytosol of cells of specific plant tissues
22
Q
cholesterol
A
sterol compound important in the composition of cell membranes
23
Q
cilia
A
in eukaryote cells, whip-like structures formed by extensions of the plasma membrane involved in synchronised movement; singular = cilium
24
colony
several individuals living together in close association
25
concentration gradient
occurs when there is a difference in solute concentration from one area to another
26
crenation
shrinking of cell due to water loss
26
covalent bonds
a type of bond between atoms where electrons are shared. The bond is very strong.
27
cytoplasm
formed by cell organelles, excluding the nucleus, and the cytosol
28
cytosol
the aqueous part of the cell
29
cytoskeleton
network of filaments within a cell
30
deoxyribonucleic acid (DNA)
nucleic acid containing the four bases — adenine, guanine, cytosine and thymine — which forms the major component of chromosomes and contains coded genetic instructions
31
electron transport chain
third stage of aerobic respiration in which electrons are transferred along a series of compounds known as cytochromes to be finally accepted by oxygen; energy released during this process results in the major yield of ATP
32
endocytosis
bulk movement of solids or liquids into a cell by engulfment
33
endoplasmic reticulum
cell organelle consisting of a system of membrane-bound channels that transport substances within the cell
34
endosymbiotic theory
suggests that certain eukaryotic organelles, like mitochondria and chloroplasts, were once free-living bacteria that were engulfed by an ancient eukaryotic cell.
35
eukaryote
any cell or organism with a membrane-bound nucleus
36
exergonic
energy-releasing chemical reaction
37
exocytosis
movement of material out of cells via vesicles in the cytoplasm
38
extremophile
microbe that lives in extreme environmental conditions, such as high temperature and low pH
39
flagella
whip-like cell organelles involved in movement; singular = flagellum
40
fluid mosaic model
a model proposing that the plasma membrane and other intracellular membranes should be considered as two-dimensional fluids in which proteins are embedded
41
fungi
any of a wide variety of organisms that have a cell wall made of chitin and reproduce by spores, including the mushrooms, moulds, yeasts, and mildews
42
glycolipids
small chains of carbohydrates (sugars) attached to the phospholipids and proteins of the plasma membrane; aid in cell recognition
43
glycolysis
a process that does not require oxygen, where glucose is broken down to pyruvate
44
glycoprotein
combination formed when a carbohydrate group becomes attached to the exposed part of a trans-membrane protein
45
Golgi apparatus
organelle that packages material into vesicles for export from a cell (also known as Golgi complex or Golgi body)
45
grana
stacks of membranes on which chlorophyll is located in chloroplasts; singular = granum
46
hydrophilic
substances that dissolve easily in water; also called polar
47
hydrophobic
substances that tend to be insoluble in water; also called non-polar
48
hypertonic
having a higher concentration of dissolved substances than the solution to which it is compared
49
hypotonic
having a lower concentration of dissolved substances than the solution to which it is compared
50
integral proteins
fundamental components of the plasma membrane that are embedded in the phospholipid bilayer
51
intermediate filaments
one of the components of the cytoskeleton of a cell, composed of protein; they form a rope-like arrangement and give mechanical support to cells
52
isotonic
having the same concentration of dissolved substances as the solution to which it is compared
53
kinetic energy
the energy associated with movement
54
endosymbiosis
a special case of symbiosis where one of the organisms lives inside the other
55
kerbs cycle
second stage of aerobic respiration, occurring mainly in mitochondria, in which pyruvate is broken down to carbon dioxide
55
lipophilic
‘lipid-loving' molecules that dissolve in lipids (hydrophobic)
55
lignin
a complex, insoluble cross-linked polymer
56
lysosome
vesicle filled with digestive enzymes
56
lipophobic
‘lipid-fearing' molecules that do not dissolve in lipids (hydrophilic)
57
lysis
bursting of a cell
58
lysosome storage disease
a disruption of normal cell function due to defective enzymes; examples include Tay–Sachs disease, Hurler syndrome, Pompe disease
59
major histocompatibility complex (MHC)
a group of proteins that have a role in the detection of invaders
60
membrane-bound organelle
an organelle that has a membrane surrounding it
61
messenger RNA (mRNA)
single-stranded RNA formed by transcription of a DNA template strand in the nucleus; mRNA carries a copy of the genetic information into the cytoplasm
62
microfilaments
one of the components of the cytoskeleton of a cell; very thin threads composed of the protein actin; they allow cells to move and change in shape
63
microscopic
anything that is not visible to the naked eye and requires a microscope to view it
64
microtubules
part of the supporting structure or cytoskeleton of a cell, made of sub-units of the protein tubulin
65
mitochondria
in eukaryotic cells, organelles that are the major site of ATP production; singular = mitochondrion
66
nuclear envelope
membrane surrounding the nucleus of a eukaryotic cell
66
nuclear pore complex (NPC)
protein-lined channel that perforates the nuclear envelope
67
nucleolus
a small, dense, spherical structure in a nucleus that is composed of RNA and produces rRNA
68
nucleic acid
a compound, such as DNA or RNA, built from nucleotide sub-units
69
nucleotides
the basic building blocks or sub-units of DNA and RNA consisting of a phosphate group, a base and a sugar
70
nucleus
in eukaryotic cells, membrane-bound organelle containing the genetic material DNA
71
organelle
any specialised structure that performs a specific function
72
organism
any living creature
73
osmosis
net movement of water across a partially permeable membrane without an input of energy and down a concentration gradient
74
osmotic flow
the net movement of water molecules from a solution of high water concentration to lower water concentration (or alternatively, from a region of low to high solute concentration)
75
peptidoglycan
polymer of sugars and amino acids that form a structure of protection outside the cell membrane of prokaryotes.
76
peripheral
proteins either anchored to the exterior of the plasma membrane through bonding with lipids or indirectly associated through interactions with integral protein
77
peroxisome
small membrane-bound organelle rich in the enzymes that detoxify various toxic materials that enter the bloodstream
78
phagocytosis
bulk movement of solid material into cells
79
phospholipid
major type of lipid found in plasma membranes
80
photosynthesis
process by which plants use the radiant energy of sunlight trapped by chlorophyll to build carbohydrates from carbon dioxide and water
81
pinocytosis
bulk movement of material that is in solution being transported into cells
82
plantae
a group of organisms that include land plants and algae. Cells have a cell wall of cellulose, a large permanent vacuole and some contain chloroplasts.
83
plasmid
small ring of DNA found in prokaryotes
84
plasmolysis
shrinking of the cytoplasm away from the wall due to water loss
85
polysaccharides
long chains of sugars joined together to form large molecules
86
pompe disease
lysosome storage disease where an absent or defective enzyme in the lysosomes does not break down glycogen and results in tissues with abnormal deposits of glycogen
87
proteins
macromolecules built of amino acid sub-units and linked by peptide bonds to form a polypeptide chain
88
Protista (protists)
a group of organisms similar in the fact that they do not fall into any other kingdom; generally unicellular; can have aspects of both plant and animal cells
89
prokaryote
any cell or organism without a membrane-bound nucleus
90
pumps
special transport proteins embedded across the plasma membrane that carry out the process of active transport
91
ribonucleic acid (RNA)
type of nucleic acid consisting of a single chain of nucleotide sub-units that contain the sugar ribose and the bases A, U, C and G
92
ribosomal RNA (rRNA)
ribosomal ribonucleic acid; synthesises proteins and is the primary component of ribosomes
93
ribosome
organelle containing RNA that is the major site of protein production in cells
94
rough endoplasmic reticulum
endoplasmic reticulum with ribosomes attached
95
sodium-potassium pump
protein that transports sodium and potassium ions against their concentration gradients to maintain the differences in their concentrations inside and outside cells
95
selectively permeable (semipermeable)
allows some substances to cross but precludes the passage of others
96
smooth endoplasmic reticulum
endoplasmic reticulum without ribosomes
97
solute
substance that is dissolved
98
solution
liquid mixture of the solute in the solvent
99
solvent
liquid in which a solute dissolves
100
stroma
in chloroplasts, the semi-fluid substance between the grana, which contains enzymes for some of the reactions of photosynthesis
101
surface area to volume ratio
a measure that identifies the number of units of surface area available to ‘serve’ each unit of internal volume of a cell, tissues or organism
102
tonoplast
in plant cells, the membrane of the plant vacuole; separates it from the rest of the cytosol
103
transcription
process of copying the genetic instructions present in DNA to messenger RNA
104
trans-membrane
proteins spanning the plasma membrane but have parts exposed to the exterior and interior of the cells
105
transfer RNA (tRNA)
a molecule made of RNA that brings amino acids to the ribosome in protein synthesis
106
turgid
swollen and distended
106
translation
process of decoding the genetic instructions in mRNA into a protein (polypeptide chain) built of amino acids
107
vacuole
structure within plant cells that is filled with fluid-containing materials in solution, including plant pigments
108
vesicle
membrane-bound sac found within a cell, typically fluid-filled; for example, a lysosome
