Glossary Flashcards
1
Q
Fossil
A
Any recognisable structure originating from an organism, or any impression that has been preserved over geological time
2
Q
Ontogeny
A
The origination and development of an organism, from fertilisation to maturity.
3
Q
Phylogeny
A
The evolutionary history of a kind of organism.
4
Q
Ultrastructure
A
The detailed structure of a biological specimen (cell, tissue, organ) observed by electron microscopy.
5
Q
DNA
A
Deoxyribosenucleic Acid - The fundamental hereditary material of all living organisms
6
Q
Protein
A
Long chain polymer of amino acids.
7
Q
Homology
A
The existence of shared ancestry between a pair of structures or genes in different species
8
Q
Paralogy
A
An anatomical similarity without shared ancestry
9
Q
Cell
A
The simplest structural unit of a living organism.
10
Q
Archaea
A
A group of single celled prokaryotic organisms that have distinct molecular characteristics separating them from bacteria.
11
Q
Bacteria
A
A large group of unicellular microorganisms with peptidoglycan cell walls, no organelles and no organised nucleus.
12
Q
Eukarya
A
Organisms made up of eukaryotic cells (genetic material in a nucleus)
13
Q
Prokaryotic
A
Prokaryotic cells are unicellular, and have no nuclei or membrane enclosed organelles.
14
Q
Peptidoglycan
A
The cell wall material of many bacteria, consisting of a single enormous molecule that surrounds the entire cell
15
Q
Circular Chromosome
A
Bacterial chromosomes contained in a circular DNA molecule
16
Q
Nucleoid
A
The region that harbours the chromosomes of a prokaryotic cell, with no membrane.
17
Q
Ribosome
A
A small particle in the cell that is the site of protein synthesis
18
Q
Flagellum
A
A long, whip like appendage that propels cells. Prokaryotic flagella differ sharply from those found in eukaryotes.
19
Q
Nucleus
A
A dense organelle present in most eukaryotic cells, typically a single rounded structure bonded by a double membrane, containing the genetic material
20
Q
Organelle
A
A membrane-bound compartment or ‘mini-organ’ within a cell with a specialised function.
21
Q
Chromosomes
A
Thread like structures of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
22
Q
Histones
A
Any group of basic proteins found in chromatin
23
Q
Chromatin
A
The material of which the chromosomes of eukaryotes are composed, consisting of protein, RNA and DNA
24
Q
Nuclear Envelope
A
The nuclear membrane, being a double membrane which surrounds the genetic material and nucleolus in eukaryotic cells.
25
Nuclear Pores
Large protein complexes that cross the nuclear envelope
26
Endomembrane System
A system of intracellular membranes that exchange material with one another, consisting of the Golgi Apparatus, Endoplasmic Reticulum and lysosomes when present.
27
Endoplasmic Reticulum
A system of membranous tubes and flattened sacs found in the cytoplasm of eukaryotes (smooth and Rough)
28
Golgi Apparatus
A system of concentrically folded membranes found in the cytoplasm of eukaryotic cells; functions in secretion from the cell by exocytosis.
29
Glycosylation
The addition of carbohydrates to another typo of molecule, such as a protein
30
Cisternae
A flattened membrane disk that makes up the Golgi Apparatus
31
Vesicles
Within the cytoplasm, a membrane enclosed compartment that is associated with other organelles such as the Golgi Apparatus
32
Glycoproteins
A protein to which sugars are attached
33
Cytoskeleton
The network of microtubules and microfilaments that gives a eukaryotic cell its shape and its capacity to arrange its organelles and move
34
Microtubules
Tubular structures made up of 13 filaments forming a cylinder found in centrioles, spindle apparatus, cilia, flagella and the cytoskeleton of eukaryotic cells
35
Microfilaments
A fibrous structure in eukaryotic cells made up of actin monomers. Play roles in the cytoskeleton, in cell movement, and in muscle contraction. They interact with myosin motors.
36
Actin
A protein that makes up the cytoskeletal microfilaments in eukaryotic cells and contractile protein of muscle
37
Intermediate Filaments
Cytoskeletal compartments found int he cells of many animal species
38
Myosin
One of the two contractile proteins of muscle
39
Dynein
A motor protein in cells which converts the chemical energy contained in ATP into the mechanical energy of movement. Also cause the movement of the flagellum - one end is permanently attached, other end walks along the other microtubule, causing them to slide against each other.
40
Kinesin
A motor protein in Eukaryotic Cells. Uses ATP to walk along microtubules carrying molecules.
41
Lipids
Non-polar, hydrophobic molecules that include fats, oils, waxes, steroids and the phospholipids that make up biological membranes
42
Sterols
Also known as Steroid alcohols, are a sub group of steroids that occur naturally in plants, animals and fungi, with an OH group (e.g. cholesterol)
43
Fatty acids
A molecule made up of a long, non-polar hydrocarbon chain and a polar carboxyl group
44
Triglycerides
Simple lipids in which three fatty acids are combined with one molecule of glycerol
45
Membranes
A phospholipid bilayer forming a barrier that separates the internal contents of a cell from the nonbiological environment, or enclosing the organelles within the cll. The membrane regulates the molecular substances entering or leaving the cell
46
Fluid mosaic model
A molecular model for the structure of biological membranes consisting of a fluid phospholipid bilayer in which suspended proteins are free to move in the plane of the bilayer
47
Differentially permeable
A semipermeable membrane is a membrane that will only allow certain molecules or ions to pass through it b diffusion, or occasionally by more specialised cases of facilitated transport
48
Diffusion
Random movement of molecules or other particles, resulting in an even distribution of the particles when no barriers are present
49
Osmosis
Movement of water across a differentially permeable membrane, from one region of high concentration towards a region of low concentration
50
Facilitated diffusion
Passive movement through a membrane involving a specific carrier protein, does not proceed against a concentration gradient
51
Active Transport
The energy dependent transport of a substance across a biological membrane against a concentration gradient
52
Endocytosis
A process by which liquids or solid particles are taken up by a cell through invagination of the cell membrane
53
Exocytosis
A process by which a vesicle within a cell fuses with the plasma membrane and releases its contents to the outside
54
Isotonic
Having the same solute concentration
55
Hypertonic
Having a greater solute concentration
56
Desmosomes
An adhering junction between animal cells
57
Plasmadesmata
Cytoplasmic strands connecting two adjacent plant cells
58
Gap Junctions
2.7nm gap between plasma membranes of two animal cells, spanned by protein channels, Gap junctions allow chemical substances or electrical signals to pass from cell to cell
59
Protein
Long chain polymer of amino acids with twenty different common side chains. Occurs with its polymer chain extended in fibrous proteins, or coiled into a compact macromolecule i.e. enzymes and other globular proteins. The component amino acids are encoded in triplets of messenger RNA, and proteins are the product of genes
60
Amino Acid
An organic compound containing both NH2 and COOH groups. Proteins are polymers of amino acids.
61
Peptide bond
The bond between amino acids in a protein; formed between a carboxyl group and an amino group (-CO-NH-) with the loss of water molecules
62
Enzymes
Catalytic proteins that speed up biochemical reactions
63
CAtalyst
A chemical substance that accelerates a reaction in which the products have higher free energy than the reactants, thereby requiring free energy input to occur.
64
Activation Energy
The energy barrier that blocks the tendency for a chemical reaction to occur
65
Allosteric inhibition
Allosteric regulation is the regulation of the activity of a protein (usually an enzyme) by the binding of an effector molecule to a site other than the active site.
66
Cofactors
Inorganic ions that are weakly bound to enzymes and required for its activity
67
Respiration
The catabolic pathways by which electrons are removed from various molecules and passed through intermediate electron carriers to O2, generating H2O and releasing energy.
68
ATP
(adenosine triphosphate) an energy storage compound containing adenine, ribose, and three phosphate groups. When it is formed from ADP, useful energy is stored; when it is broken down (to ADP or AMP), energy is released to drive endergonic reactions
69
Aerobic
In the presence of oxygen; requiring or using oxygen
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Anaerobic
Occurring without the use of O2
71
Fermentation
The anaerobic degradation of a substance such as glucose to smaller molecules such as lactic acid or alcohol (ethanol) with the extraction of energy
72
NAD+ and NADH
(nicotinamide ademine dinucleotide) A coenzyme which acts as an electron carrier in redox reactions, especially in glucose metabolism. Exists in an oxidised (NAD+) and reduced (NADH) form. The oxidation is highly exergonic, so NADH is able to hold lots of energy which can later be transferred to ATP
73
FAD and FADH2
Another electron carrier in glucose metabolism
74
Reduction
Gain of electrons by a chemical reactant
75
Oxidation
Loss of electrons by a chemical reactant
76
Glycolisis
The enzymatic breakdown of glucose to pyruvic acid
77
Kreb's Cycle
(Citric Acid Cycle/TCA Cycle) In cellular respiration, a set of chemical reactions whereby acetyl CoA is oxidised to carbon dioxide and Hydrogen atoms are stored as NADH and FADH2
78
Oxidative Phosphorylation
ATP formation in the mitochondrion, associated with the flow of electrons through the respiratory chain
79
Mitochondria
Energy generating organelles in eukaryotic cells that contain the enzymes of the citric acid cycle, the respiratory chain and oxidative phosphorylation
80
Respiratory Chain
The terminal reactions of cellular respiration, in which electrons are passed from NAD or FAD, through a series of intermediate carriers, to molecular oxygen with the concomitant production of ATP
81
Cristae
Folds in the inner membrane of mitochondria, giving the inner membrane its characteristic wrinkled shape and providing a large amount of surface area for chemical reactions to occur on.
82
Mitochondrial matrix
The fluid interior of a mitochondrion, enclosed y the inner mitochondrial membrane
83
Plastids
A class of plant organelles that includes the chloroplast. The site of manufacture and storage of important chemical compounds used by the cell.
84
Chloroplast
An organelle bounded by a double membrane containing the enzymes and pigments that perform photosynthesis. Chloroplasts appear only in eukaryotes.
85
Thylakoids
A flattened sac within a chloroplast. Thylakoid membranes contain all of the chlorophyll in a plant, in addition to electron carriers of phosphorylation. Thylakoids stack to form grana
86
Stroma
The fluid contents of an organelle such as a chloroplast or mitochondria
87
Endosymbriosis
The theory that the eukaryotic cell evolved via the engulfing of one prokaryotic cell by another
88
Centromere
The region where sister chromatids join
89
Centrosome
The major microtubule organising centre of animal cell
90
Centriole
A paired organelle that helps organise the microtubules in animal and protist cells during nuclear division.
91
Chromatin
The nucleic acid protein complex that makes up eukaryotic chromosomes
92
Chromatid
A newly replicated chromosome, from the time molecular duplication occurs until the time the centromeres separate (during anaphase of mitosis or of meiosis II)
93
Chromosome
In bacteria and viruses, the DNA molecule that contains most or all of the genetic information of the cell or virus. In eukaryotes, a structure composed of DNA and proteins that bears part of the genetic information of the cell
94
Kinetechore
Specialised structure on a centromere to which microtubules attach
95
Spindle
Array of microtubules emanating from both poles of a dividing cell during mitosis and playing a role in the movement of chromosomes at nuclear division
96
Macromolecule
A giant (molecular weight > 1000) polymeric molecule. The macromolecules are the proteins, polysaccharides and nucleic acids
97
Polymer
A large molecule mad up of similar or identical subunits called monomers
98
Condensation
A chemical reaction in which two molecules become connected by a covalent bond and a molecule of water is released (AH + BOH -> AB + H2O)
99
Carbohydrates
Organic compounds containing carbon, hydrogen and oxygen in the ration 1:2:1 (sugars, starch and cellulose)
100
Polysaccharide
A macromolecule composed of many monosaccharides (simple sugars) - Cellulose and Starch
101
Monosaccharide
A simple sugar. Oligosaccharides and polysaccharides are made up of monosaccharides.
102
Nucleic Acid
A polymer made up of nucleotides, specialised for the storage, transmission and expression of genetic information
103
Phosphodiester bond
The connection in a nucleic acid strand, formed by linking two nucleotides
104
Nucleotide
The basic chemical unit in nucleic acids, consisting of a pentose sugar, a phosphate group and a nitrogen containing base
105
Purine
One of the two types of nitrogenous bases in nucleic acids. Each of the purines - adenine and guanine - pairs with a specific pyrimidines
106
Pyrimidine
One of the two types of nitrogenous bases in nucleic acids. Each of the pyrimidines -cytosine, thymine and uracil - pairs with a specific purine.
107
Nitrogenous base
A nitrogen containing molecule that has the same chemical properties as a base, that is attached to each sugar in the sugar phosphate backbone of nucleic acids.
108
Base pair
In double stranded DNA, a pair of nucleotides formed by the complementary base pairing of a purine on one strand and a pyrimidine on the other
109
Genetic code
The set of instructions, in the form of nucleotide triplets, that translate a linear sequence of nucleotides in mRNA into a linear sequence of amino acids in a protein
110
Internal Environment
In multicellular organisms, includes blood plasma and intestitial fluid. i.e. the extracellular fluids that surround cells
111
Interstitial Fluid
Extracellular fluid that is not contained in the vessels of a circulatory system
112
Homeostasis
The maintenance of a steady state, such as a constant temperature, by means of physiological or behavioural feedback responses
113
Epithelial Tissue
A type of animal tissue made up of sheets of cells that lines or covers organs, makes up tubules, and covers the surface of the body (squamous, columnar, cuboidal, stratified)
114
Muscle Tissue
Excitable tissue that can contract through the interactions of actin and myosin. There are three types: skeletal, smooth and cardiac
115
Connective tissue
A type of tissue that connects or surrounds other tissues; its cells are embedded in a collagen-containing matrix. Includes cartilage, blood, bone and fat
116
Nervous Tissue
Tissue specialised for processing and communicating information
117
Neuron
A nervous system cell that can generate and conduct action potentials along an axon to a synapse with another cell
118
Glial Cells
One of the two classes of neural cells; glia do not typically conduct action potentials
119
Ectotherm
An animal that is dependent on external heat sources for regulating its body temperature
120
Endotherm
An animal that can control its body temperature by the expenditure of its own metabolic energy
121
Hypothermia
Below-normal body temperature
122
Hibernation
The state of inactivity of some animals during winter; marked by a drop in body temperature and metabolic reate
123
Basal Metabolic Rate
The minimum rate of energy turnover in an awake (but resting) bird or mammal that is not expending energy for thermoregulation
124
Beta Pleated Sheet
A type of protein secondary structure, results from hydrogen bonding between polypeptide regions running antiparallel to one another
125
Alpha Helix
A prevalent type of secondary protein structure. A right hand helix.
126
Signal Transduction Pathway
The series of biochemical steps whereby a stimulus to a cell (such as a hormone or neurotransmitter binding to a receptor) is translated into a response of the cell.
127
Autocrine
A chemical signal that binds and affects the cell that makes it
128
Paracrine
A chemical signal that acts locally, near the site of its secretion.
129
Receptor Protein
A protein that can bind to a specific molecule, or detect a specific stimulus, within the cell or in the cell's external environment. Receptors can be located in the cell membrane, the cytoplasm or the nucleus.
130
Ion Channel
An integral membrane protein that allows ions to diffuse across the membrane in which it is embedded
131
Protein Kinase
An enzyme that catalyses the addition of a phosphate group from ATP to a target protein
132
Protein Kinase Cascade
A series of reactions in response to a molecular signal, in which a series of protein kinases activate one another in a sequence, amplifying the signal at each step
133
G Protein
A membrane protein involved in signal transduction, characterised by binding GDP or GTP
134
G Protein-linked receptors
A class of receptors that change configuration upon ligand binding such that a G protein binding site is exposed on the cytoplasmic domain of the receptor, initiating a signal transduction pathway.
135
Effector Protein
In cell signalling, a protein responsible for the cellular response to a signal transduction pathway
136
Second Messenger
A compound, such as cAMP, that is released within a target cell after a hormone (the first messenger) has bound to a surface receptor on a cell; the second messenger triggers further reactions within the cell
137
Hormone
A chemical signal produced in minute amounts at one site in a multicellular organism and transported to another site where it acts on target cells
138
Neurohormone
A chemical signal produced and released by neurones and subsequently acts as a hormone
139
Tropic Hormones
Hormones produced by the anterior pituitary that control the secretion of hormones by other endocrine glands
140
Endocrine Gland
An aggregation of secretory cells that secretes hormones into the blood. The endocrine system consists of all endocrine cells and glands in the body that produce and release hormones
141
Exocrine gland
Any gland that secretes molecules into a duct
142
Hypothalamus
The part of the brain lying below the thalamus; it coordinates water balance, reproduction, temperature regulation and metabolism
143
Anterior Pituitary
The portion of the vertebrate pituitary gland that derives from gut epithelium. Produces Tropic Hormones.
144
Posterior Pituitary
A portion of the pituitary gland derived from neural tissue; involved in the storage and release of antidireutic hormone (ADH) and oxytocin
145
Negative Feedback
In regulatory systems, information that decreases a regulatory response, returning the system to the set point
146
Fight or Flight Response
A rapid physiological response to a sudden threat mediated by the hormone epinephrine/adrenalin.
147
Neuron
A nervous system cell that can generate and conduct action potentials along an axon to a synapse with another cell
148
Dendrites
Branching fibres (processes) of a neuron. Dendrites are usually short compared with the axon, and commonly receive information then carry it to the neuronal cell body
149
Axon
The process (branching structure) of a neuron that conducts action potentials away from the cell body
150
Axon Terminal
The end portion of an axon, which passes information to another cell. Axon terminals form synapses with other cells and release neurotransmitters
151
Glia
One of the two classes of neural cells; glia support, nourish and insulate neurons.
152
Central Nervous System (CNS)
The portion of the nervous system that is the site of most information processing, storage, and retrieval; in vertebrates, the brain and spinal cord.
153
Peripheral Nervous System (PNS)
The portion of the nervous system that transmits information to and from the central nervous system, consisting of neurons that extend or reside outside the brain or spinal cord and their supporting cells
154
Afferent Neurons
Neurons that carry impulses towards the central nervous system (Sensory Neurons)
155
Efferent Neurons
Neurons that carry impulses outward from the central to the peripheral nervous system (Motor Neurons)
156
Interneuron
A neuron that communicates information between two other neurons
157
Sensory System
A set of organs and tissues for detecting a stimulus; consists of sensory cells, the associated structures, and the neural networks that process the information
158
Synapse
A specialised type of junction where a neuron meets its target cell (which can be another neuron or some other type of cell) and information in the form of neurotransmitter molecules is exchanged across a synaptic clerft
159
Synaptic Cleft
The space between the presynaptic cell and the postsynaptic cell
160
Presynaptic Cell
The neuron that transmits information to another cell at a synapse
161
Postsynaptic Cell
The cell that receives information from a neuron at a synapse
162
Neurotransmitter
A substance produced in and released by a neuron (the presynaptic cell) that diffuses across a synapse and excites or inhibits another cell (the postsynaptic cell)
163
Myelin
Concentric layers of plasma membrane that form a sheath around some axons; myelin provides the axons with electrical insulation and increases the rate of transmission of action potentials
164
Oligodendrocyte
A type of glial cell that myelinates axons in the central nervous system
165
Schwann Cell
A type of glial cell that myelinates axons in the peripheral nervous system
166
Cerebrum
The dorsal anterior portion of the forebrain, making up the largest part of the mammalian brain; the chief coordination centre of the nervous system and the major information processing areas of the vertebrate brain, consists of two cerebral hemispheres
167
Cerebral Cortex
The thin layer of grey matter (neuronal cell bodies) that overlies the cerebrum
168
Cerebellum
The brain region that controls muscular coordination; located at the anterior end of the hindbrain
169
Brainstem
The portion of the vertebrate brain between the spinal cord and the forebrain, made up of the medulla, pons and midbrain
170
Frontal Lobe
The largest of the brain lobes in humans; involved with feeling and planning functions; includes the primary motor cortex
171
Parietal Lobe
Processes complex stimuli and includes the primary somatosensory cortex
172
Temporal Lobe
Receives and processes auditory and visual information; involved in recognising, identifying and naming objects
173
Occipital Lobe
Processes visual information
174
Gyri and Sulci
Respectively, the ridges and valleys of the foldings of the vertebrate brains cerebral cortex
175
Association Cortex
In the vertebrate brain, the portion of the cortex involved in higher-order information processing, so named because it integrates, or associates, information from different sensory modalities and from memory
176
Antigen
Any substance that stimulates the production of an antibody or antibodies in the body of a vertebrate
177
Antigen determinant
The specific region of an antigen that is recognised and bound by a specific antibody.
178
Antigen presenting cell
In cellular immunity, a cell that ingests and digests an antigen and then exposes fragments of that antigen to the outside of the cell, bound to proteins in the cell's plasma membrane
179
B cell
A type of lymphocyte involved in the humoral immune response of vertebrates. Upon recognising an antigenic determinant, a B cell develops into a plasma cell, which secretes an antibody
180
Antibody
One of the myriad proteins produced by the immune system that specifically binds to a foreign substance in blood or other tissue fluids and initiates its removal from the body
181
Complement
A group of 11 proteins that play a role in some reactions of the immune system (not immunoglobulins). They attach to substances on the pathogen or to an antibody bound to pathogen and help phagocytes to recognise and kill the pathogen.
182
Cytokine
A regulatory protein made by immune system cells that affects other target cells in the immune system
183
Histamine
A substance released by damaged tissue, or by mast cells in response to allergens. Histamine increases vascular permeability, leading to edema (swelling).
184
Immunogen
An antigen or any substance that may be specifically bound by components of the immune system
185
Inflammation
A nonspecific, innate defence against pathogens; characterised by redness, swelling, pain and increased temperature
186
Leukocytes
White Blood Cells - cells in the blood plasma that play defensive roles in the immune system
187
Lymphocytes
One of the two major classes of white blood cells; includes T cells, B cells, and other cell types important in the immune system
188
Lymphatic System
A system of vessels that returns interstitial fluid to the blood
189
Lymph
A fluid derived from blood and other tissues that accumulates in intercellular spaces throughout the body and is returned to the blood by the lymphatic system
190
Lymph Node
A specialised structure in the lymph vessels of the lymphatic system. Lymph nodes contain lymphocytes, which encounter and respond to foreign cells and molecules in the lymph as it passes through the vessels
191
T cell
A type of lymphocyte involved in the cellular immune response. The final stages of its development occur in the Thymus gland.
192
T-helper cell
Type of T cell that stimulates events in both the cellular and the humoral immune responses by binding to the antigen on an an antigen-presenting cell (target of HIV-I)
193
T-cytotoxic cell
Cell of the cellular immune system that recognise and directly eliminate virus-infected cells
194
T cell receptors
Proteins on the surface of a T cell that recognises the antigenic determinant for which the cell is specific
195
Major Histocompatibility Complex (MHC)/ MHC Molecules
MHC is a group of genes that code for membrane bound glycoproteins that direct recognition of self from non-self.
Class I found on all nucleated cells, when infected display pathogen or abnormal antigens to be recognised as non-self by T-helper cells.
Class II found on macrophages, B cells and dendritic cells, present pathogen antigens to T-helper cells.
196
Macrophage
Phagocyte that engulfs pathogens by endocytosis
197
Phagocyte
One of the two major classes of white blood cells; one of the non specific defences of animals; ingests invading microorganisms by phagocytosis.
198
Mast Cells
Cells, typically found in connective tissue near barriers of internal/external environment, that release histamine in response to tissue damage
199
Memory Cell
Long-lived lymphocytes produced after exposure to an antigen. They persist in the body and are able to mount a rapid response to subsequent exposures of the antigen
200
Plasma cell
An antibody secreting cell that develops from a B cell; the effector cell of the humoral immune response
201
Pathogen
An organism that causes disease
202
Immunity
In animals, the ability to avoid disease when invaded by a pathogen by deploying various defence mechanisms
203
Immunological memory
The capacity to more rapidly and massively respond to a second exposure to an antigen than occurred on the first exposure.
204
Vaccination
Injection of a weakened/attenuated virus or bacteria or their proteins into the body, to induce immunity
205
Humoral Immune Response
The response of the immune system mediated by B cells that produces circulating antibodies active against extracellular bacteria and viral infections
206
Cellular Immune Response
Immune response mediated by T cells and directed against parasites, fungi, intracellular viruses and foreign tissues (grafts).
207
Totipotent
Possessing all of the genetic information and other capacities necessary to form an entire individual organism
208
Pluripotent
Having the ability to form all of the cells in the body
209
Multipotent
Having the ability to differentiate into a limited number of cell types
210
Embryonic Stem (ES) cell
Pluripotent cells in the blastocyst
211
induced Pluripotent Stem (iPS) cell
Multipotent or pluripotent animal stem cell produced from differentiated cells in vitro by the addition of several genes that are expressed
212
Somatic Stem Cell
Multipotent bodily cell
213
Stem Cell
In animals, an undifferentiated cell that is capable of continuous proliferation. Generates more stem cells and a large clone of differentiated progeny cells.
214
Zygote
The cell created by the union of two gametes, in which the gamete nuclei are also fused.
215
Blastocyst
An early embryo formed by the first divisions of the fertilised egg (zygote). In mammals, a hollow ball of cells.
216
Trophoblast
At the 32-cell stage of mammalian development, the outer group of cells that will become part of the placenta and thus nourish the growing embryo
217
Inner Cell Mass
Will give rise to the yolk sac and embryo
218
heterotrophs
An organism that requires performed organic molecules as food
219
Autotroph
An organism that is capable of living exclusively on inorganic materials, water, and some energy source such as sunlight or chemically reduced matter
220
Macronutrients
A mineral element required in large amounts
221
Micronutrient
A mineral element required in concentrations of less than 100 micrograms per day
222
Vitamin
An organic compound that an organism cannot synthesise but nevertheless requires in small quantities for normal growth and metabolism
223
Vitamin B1, Thiamin
Coenzyme in cellular respiration. Deficiency causes muscle weakness (beriberi), weight loss, irritability, loss of appetite and forgetfulness. In fresh vegetables, fruit, liver, cereals and yeast. Non Fat Soluble.
224
Vitamin C, abscorbic acid
Aids formation of connective tissues, prevents oxidation of cellular constituents. Deficiency is scurvy: exhaustion and weakness, softening of gums, foul breath, diarrhoea. In fresh fruit and veg. Non Fat Soluble.
225
Vitamin D, Calciferol
Aids absorption of calcium and phosphorus. Deficiency is rickets, or sub-clinically, depression. In sunlight and milk. Fat soluble.
226
Essential Amino Acids
Amino Acids that an animal cannot synthesise for itself and must obtain from food (8 of them).
227
Essential Fatty Acids
Fatty acids that an animal cannot synthesise for itself and must obtain from food.
228
Saprobes
Organisms that obtain carbon and energy directly form dead organic matter.
229
Detritivores
Organisms that obtain energy from waste products of other organisms
230
Filter Feeders
Organisms that trap tiny particles or organisms suspended in water
231
Predators
Organisms that catch and kill other organisms for food
232
Leptin
A hormone produced by fat cells that is believed to provide feedback information to the hypothalamus about the status of the body's fat reserves
233
Physical Digestion
Physical breakdown of food to smaller particles by grinding or chewing to increase surface area
234
Enzymatic Digestion
Breakdown of complex molecules by hydrolytic enzymes into monomers that can be absorbed and utilised by cells
235
Incisors
Teeth for cutting, chopping or gnawing
236
Canines
Teeth for stabbing, ripping and shredding
237
Molars and Premolars
Teeth for shearing, crushing and grinding
238
Amylase
An enzyme found in saliva and secreted by the pancreas that catalyses the hydrolysis of starch, usually to maltose or glucose
239
Peristalsis
Wavelike muscular contractions proceeding along a tubular organ, propelling the contents along the tube
240
Gastric Pits
Deep infoldings in the walls of the stomach lined with secretory cells
241
Chief Cells
One of three types of secretory cell found in the gastric pits of the stomach wall. Chief cells secrete pepsinongen, which becomes the protein digesting-enzyme pepsin.
242
Parietal Cells
One of three types of secretory cell found in the gastric pits of the stomach wall. Parietal cells produce hydrochloric acid (HCl), via a chloride bicarbonate exchange using cotransport across the membrane. Thos creates an acidic environment that destroys many of the harmful organisms ingested with food and converts pepsinogen to pepsin.
243
Mucosal Epithelium
An epithelial cell layer containing cells that secrete mucus
244
Bile
A secretion of the liver made up of bile salts synthesised from cholesterol, various phospholipids and bilirubin (the breakdown product of haemoglobin). Emulsifies fats in the small intestine
245
Lipase
An enzyme secreted by the pancreas that breaks down fats into di and monoglycerides, fatty acids and glycerol
246
Trypsin
An enzyme secreted by the pancreas that breaks down proteins to large peptides
247
Carboxypeptidase
An enzyme secreted by the pancreas that targets the COOH end of peptides and breaks them down to smaller peptides and amino acids
248
Aminopeptidase
An enzyme of the small intestine that targets the amine end of peptides and breaks them down to smaller peptides and amino acids
249
Duodenum
The beginning portion of the vertebrate small intestine, the site of most digestion
250
Dejunum
The middle division of the small intestine, where most absorption of nutrients occurs
251
Ileum
The final segment of the small intestine
252
Nuclease
Nucleic Acids --> Nucleotides
253
Maltase
Maltose --> Glucose
254
Lactase
Lactose --> Galactose and Glucose
255
Sucrase
Sucrose --> Fructose and Glucose
256
Enteric NErvous System
The nerve nets in the submucosa and between the smooth muscle layers of the vertebrate gut. Control the gut and in constant communication with the CNS
257
Villi
Hairlike projections from the walls of the small intestine. Have microvilli. Increase surface area for digestion.
258
Circulatory System
A physiological system consisting of a muscular pump (heart), a fluid (blood or haemolymph), and a series of conduits (blood vessels) that transports materials around the body.
259
Open Circulatory System
Circulatory system in which extracellular fluid leaves the vessels of the circulatory system, percolates between cells and through tissues, and then flows back into the circulatory system to be pumped out again.
260
Closed Circulatory System
Circulatory System in which the circulating fluid is contained within a continuous series of vessels.
261
Atrium
In the hearts of vertebrates, the thin walled chamber(S) entered by blood on its way to the ventricle(s)
262
Ventricle
A muscular heart chamber that pumps blood through the lungs or through the body.
263
Systemic Circulation
Portion of the circulatory system by which oxygenated blood from the lungs or gills is distributed throughout the rest of the body and returned to the heart.
264
Pulmonary Circulation
Portion of the circulatory system by which blood is pumped from the heart to the gills or lungs for oxygenation and back to the heart for distribution.
265
Aorta
The main trunk of arteries leading to the systemic circulation
266
Vena Cavae
In the circulatory systems of crocodilians, birds and mammals, large veins that empty into the right atrium of the heart
267
Tricuspid (mitral) valve
The valve between the left atrium and the left ventricle of the heart
268
Aortic Valve
A one-way valve between the left ventricle of the heart and the aorta that prevents back-flow into the ventricle when it relaxes
269
Pulmonary Valve
A one-way valve between the right ventricle of the heart and the pulmonary artery that prevents back-flow of blood into the ventricle when it relaxes.
270
Systold
Contraction of a chamber of the heart, driving blood forward in the circulatory system
271
Diastole
The portion of the cardiac cycle when the heart muscle relaxes.
272
Cardiomyopathy
Chronic disease of the heart muscle. Can be dilated (weak and enlarged heart), hypertrophic (heart muscle is thickened), or restrictive (heart muscle is stiff).
273
Artery
A muscular blood vessel carrying blood away from the heart to other parts of the body. Arteries have more elastin, more smooth muscle and more fibrous collagen in the tunica adventitia. Blood is under high pressure.
274
Arteriole
A small blood vessel arising from an artery that feeds blood into a capillary bed. A resistance vessel.
275
Vein
A blood vessel that returns blood to the heart. Veins have less collagen, elastin and smooth muscle. Blood is under low pressure and there are valves to prevent back-flow. Veins are capacitance vessels.
276
Venule
A small blood vessel draining a capillary bed that joins others of its kind to form a vein
277
Capillary Beds
Networks of capillaries where materials are exchanged between the blood and interstitial fluid
278
Vascular Smooth Muscle
The smooth muscle that makes up blood vessels
279
Endothelium
The single layer of epithelial cells lining the interior of a blood vessel
280
Osmotic pressure
The force driving fluid into capillaries because of differences in water potential
281
Artherosclerosis
A disease of the arteries characterised by the deposition of fatty material on their inner walls.
282
Sphygmomanometer
An instrument for measuring blood pressure, typically consisting of an inflatable rubber cuff which is applied to the arm, enabling the determination of systolic and diastolic blood pressure by increasing and gradually decreasing the pressure in the cuff. Tapping = systolic, end of whoosh = diastolic
283
Pacemaker cells
Cardiac cells that can initiate action potentials without stimulation from the nervous system, allowing the heart to initiate its own contractions
284
Sinoatrial node
The pacemaker of the mammalian heart, initiates action potentials that spread throughout the atria, resulting in a contraction.
285
Atrioventricular node
A modified node of cardiac muscle that organises the action potentials that control contraction of the ventricles.
286
Bundle of His
Fibres of modified cardiac muscle that conduct action potentials from the atria (AVN) to the ventricular muscle mass.
287
Purkinje Fibres
Branches of the Bundle of His
288
Autonomic Nervous System
The portion of the peripheral nervous system that controls involuntary functions
289
Mean arterial pressure
Average blood pressure in an individual over a single cardiac cycle
290
Sympathetic Nervous System
The division of the autonomic system that works on fight or flight response
291
Parasympathetic nervous system
The division of the autonomic nervous system that is rest and digest
292
Adrenalin
The "fight or flight" hormone produced in the medulla of the adrenal gland. Also functions as a neurotransmitter.
293
Noradrenalin
A neurotransmitter found in the CNS and also at the postganglionic nerve endings of the sympathetic nervous system. Causes vasoconstriction
294
Nitric Oxide
An unstable molecule that serves as a second messenger causing smooth muscle to relax
295
Barorecptor
A pressure sensing cell or organ
296
Chemoreceptor
A sensory receptor cell that senses specific molecules in the environment
297
Vasoconstriction
Constriction of blood vessels
298
Vasodilation
Dilation of blood vessels
299
Internal respiration
Occurs in the metabolising tissues, where oxygen diffuses out of the blood and Carbon Dioxide out of the cells
300
External Respiration
Occurs in the lungs, where oxygen diffuses into the blood and carbon dioxide into the air
301
Aerobic Respiration
The process of producing cellular energy in the presence of oxygen
302
Ventilation
Physically breathing
303
Oxygen Binding Curve
The affinity of oxygen carrier proteins for oxygen at different partial pressures
304
Partial Pressure
The component of total pressure exhibited by a single free gas within a mixture of gasses
305
Respiratory Pigments
A molecule that increases the oxygen-carrying capacity of blood.
306
Haemoglobin
Oxygen-transporting protein found in red blood cells of vertebrates and some invertebrates. Consists of four peptide units, each with a haeme group.
307
Myoglobin
An oxygen -binding molecule found in muscle. Consists of a haeme unit and a single globin chain; carries less oxygen that haemoglobin but has a greater affinity for it.
308
Gill
An organ specialised for gas exchange with water. Water flows in one direction over the lamellae and oxygen diffuses into the bloodstream
309
Operculum
The protective cover of a gill
310
Bronchus
The major airway(s) branching off the trachea into the vertebrate lung
311
Bronchioles
The smallest airways in the vertebrate lung, branching off the bronchi.
312
Trachea
A tube that carries air to the bronchi of the lungs of vertebrates
313
Surfactant
A substance that decreases the surface tension of a liquid. Lung surfactant, secreted by cells of teh alveoli, is mostly phospholipid and decreases the amount of work necessary to inflate the lungs.
314
Thoracic Cavity
The portion of the mammalian body cavity bounded by the ribs, shoulders, and diaphragm. Contain the heart and lungs.
315
Pleural Cavity.
The thin, fluid filled space between the two pulmonary plurae (visceral and parietal) of each lung
316
Diaphragm
A sheet of muscle that separates the thoracic and abdominal cavities in mammals; responsible for breathing
317
Intercostal Muscles
Muscles between the ribs that can augment breathing movements by elevating and suppressing the ribcage
318
Hypoxia
A deficiency of oxygen
319
Hypocapnia
A deficiency of carbon dioxide
320
Osmoconformer
An aquatic animal that equilibrates the osmolarity of its extracellular fluid to be the same as that of the external environment
321
Osmoregulator
An aquatic animal that actively regulates the osmolarity of its extracellular fluid
322
Osmolarity
The concentration of osmotically active particles in a solution
323
Hypoosmotic
A solution with a lesser concentration of solute
324
Hyperosmotic
A solution with a higher concentration of solute
325
Renal cortex
The outer portion of the kidneys between the renal capsule and the renal medulla. Contains the "heads" of nephrons.
326
Renal Medulla
The innermost portion of the kidneys. Contains the "tails" of nephrons
327
Ureter
Long duct leading from the vertebrate kidney to the urinary bladder
328
Nephron
The functional unit of the kidney, consisting of a structure for receiving a filtrate of blood and a tubule that reabsorbs selected parts of the filtrate
329
Glomerulus
Sites in the kidney where blood filtration takes place. Each glomerulus consists of a knot of capillaries served by afferent and efferent arterioles.
330
Bowman's Capsule
An elaboration of the renal tubule, composed of podocytes, that surrounds and collects the filtrate from the glomerulus
331
Renal Tubule
A structural unit of the kidney that collects filtrate from the blood, reabsorbs specific ions, nutrients, and water and returns them to the blood, and concentrates excess ions and waste products such as urea for excretion from the body
332
Renal Filtrate
The contents of the renal tubule
333
Aquaporins
A transport protein in plant and animal cell membranes through which water passes in osmosis.
334
Proximal Convoluted Tubule
The initial segment of the renal tubule in the kidney, closest to the glomerulus. PCT cells actively transport out Na+, amino acids and glucose from the renal filtrate, causing water to follow by osmosis and be picked up by the Vasa Recta
335
Loop of Henle.
Long, hairpin loop of the mammalian renal tubule that runs from the cortex down into the medulla and back to the cortex; creates a concentration gradient in the interstitial fluids of the medulla
336
Distal Convoluted Tubule
The portion of a renal tubule from where it reaches the renal cortex, just past the loop of Henle, to where it joins a collecting duct. Renal fluid becomes isotonic here.
337
Collecting Duct
In vertebrates, a tubule that receives urine produced in the nephrons of the kidney and delivers that fluid to the ureter for excretion. Water reabsorption occurs here, harvesting the concentration gradient set up by the loop of Henle.
338
Antideuretic Hormone
(ADH or Vasopressin). A hormone that promotes water reabsorption by the kidney. Produced by neurons in the hypothalamus and released from nerve terminals in the posterior pituitary
339
Haemorrhage
Excessive Bleeding
340
Renin
An enzyme released from the kidneys in response to a drop in the glomerular filtration rate. Together with angiotensin converting enzyme (ACE), converts angiotensinogen into angiotensin.
341
Angiotensin
A peptide hormone that raises blood pressure by causing peripheral vessels to constrict. Also maintains glomerular filtration by constricting efferent vessels and stimulates thirst and the release of aldosterone.
342
Aldosterone
A steroid hormone produced in the adrenal cortex of mammals. Promotes secretion of potassium and reabsorption of sodium in the kidney. Increases water reabsorption.
343
Taxonomy
The branch of science concerned with classification, especially of organisms.
344
Protostome
Bilateria where the blastopore forms the mouth
345
Deuterostome
Bilateria where the blastopore forms the anus
346
Blastopore
The opening created by the invagination of the vegetal pore during gastrulation of animal embryos.
347
Bilateral Symmetry
The condition in which only the right and left sides of an organism, divided by a single plane through the midline, are mirror images of each other.
348
Radial Symmetry
The condition in which any two halves of a body are mirror images of each other, providing the cut passes through the centre.
349
Coelom
An animal body cavity, enclosed by muscular mesoderm and lined with a mesodermal layer called peritoneum that also surrounds the internal organs.
350
Ectoderm
The outermost of the three embryonic germ layers first delineated during gastrulation. Gives rise to the skin, sense organs, and nervous system.
351
Endoderm
The innermost of the three embryonic germ layers delineated during gastrulation. Gives rise to the digestive and respiratory tracts and structures associated with them.
352
Mesoderm
The middle of the three embryonic germ layers first delineated during gastrulation. Gives rise to the skeleton, circulatory system, muscles, excretory system and most of the reproductive system.
353
Clade
A monophyletic group made up of an ancestor and all its descendants.
354
Notochord
A flexible rod of gelatinous material serving as a support in the embryos of all chordates and in the adults of tunicates and lancelets.
355
Amnion
The fluid filled sac within which the embryos of reptiles, birds and mammals develop.
356
Paraphyletic
Pertaining to a group containing the common ancestor but not all its descendents
357
Polyphyletic
Pertaining to a group that consists of multiple distantly related organisms, and does not include the common ancestor of the group.
358
Monophyletic
Pertaining to a group that consists of an ancestor and all of its descendants.
359
Platyhelminthes
Protostome
Flat worms
acoelomate - eg. tape worm
360
Anelida
Protostome
Earthworms, leeches, polychatae worms
segmented body plan
361
Mollusca
```
Protostome
Ancestral Shell and mantle
Gastropods (slugs and snails)
Bivalves (clams, oysters, mussels)
Cephalopods (squid, cuttlefish, octopi)
```
362
Nematoda
Protostome
| eg hookworm, pinworm guinea worm
363
Arthropoda
```
Protostome
exoskeleton and jointed appendages
- arachnida (class)
- crustacea
- insecta
```
364
Germ Cells
A reproductive cell or gamete of multicellular organisms
365
Somatic Cell
All the cells of the body that are not specialised for reproduction
366
Oviparity
Reproduction in which eggs are released by the female and development is external to the mother;s body
367
Viviparity
Reproduction in which fertilization of the egg and development of the embryo occur inside the mother's body
368
Gametogenesis
The specialised series of cellular divisions that leads to the production of gametes
369
Oogenesis
Gametogenesis leading to production of an ovum
370
Spermatogenesis
Gametogenesis leading to the production of sperm
371
Budding
Asexual Reproduction in which a more or less complete new organism grows from the body of the parent organism, eventually detaching itself.
372
Regeneration
The development of a complete individual from a fragment of an organism
373
Parthenogenesis
Production of an organism from an unfertilised egg.
374
Spermatogonia
In animals, the diploid progeny of a germ cell in males
375
Spermatid
One of the products of the second meiotic division of a primary spermatocyte; four haploid spermatids which remain connected by cytoplasmic bridges are produced. for each primary spermatocyte that goes into meiosis
376
Primary Spermatocyte
The diploid progeny of a spermatogonium; undergoes the first meiotic division to form secondary spermatocytes
377
Secondary Spermatocyte
One of the products of the first meiotic division of a primary spermatocyte.
378
Sertoli Cells
Cells in the seminiferous tubules that nurture the developing sperm
379
Seminiferous tubules
The tubules within the testes within which sperm production occurs
380
Oogonia
In animals, the diploid progeny of a germ cell in females
381
Primary Oocyte
The diploid progeny of an oogonium. In many species, a primary oocyte enters prophase of the first meiotic division, then remains in developmental arrest for a long time before resuming meiosis to form a secondary oocyte and a polar body
382
Secondary Oocyte
In oogenesis, the daughter cell of the first meiotic division that receives almost all the cytoplasm
383
Polar body
A nonfunctional nucleus produced by meiosis during oogenesis
384
Ootid
In oogenesis, the daughter cell of the second meiotic division that differentiates into the mature ovum
385
Follicle
In female mammals, and immature egg surrounded by nutritive cells
386
Corpus Luteum
A structure formed from a follicle after ovulation; produces hormones important to the maintenance of pregnancy
387
Fertilisation
Union of gametes
388
Zona Pellucida
A jelly-like substance that surrounds the mammalian ovum when it is released from the ovary
389
Acrosome
The structure at the forward tip of an animal sperm which is the first to fuse with the egg membrane and enter the egg cell
390
Epididymus
Coiled tubules in the testes that store sperm and conduct sperm from the seminiferous tubules to the vas deferens
391
Vas deferens
Duct that transfers sperm from the epididymus to the urethra
392
Gonadotropin Releasing Hormone
Hormone produced by the hypothalamus that stimulates the anterior pituitary to secrete gonadotropins
393
Luteinizing Hormone
A gonadotropin produced by the anterior pituitary that stimulates the gonads to produce sex hormones
394
Follicle Stimulating Hormone
A gonadotropin produced by the anterior pituitary
395
Leydig Cells
Cells between the sertoli cells in the testes that produce testosterone
396
Theca Cells
Comprise a layer of ovarian follicles. Produce testosterone from cholesterol in the presence of LH
397
Granulosa
A somatic cell of the sex cord that is closely associated with the developing female gamete. Produces oestrodiol from testosterone in the presence of FSH
398
Oestrogen
Any of several steroid sex hormones; produced chiefly by the ovaries in mammals
399
Progesterone
A female sex hormone that maintains pregnancy
400
holoblastic cleavage
Embryo cell cleavage that occurs in the absence of a large concentration of yolk, complete cleavage.
401
Blastomere
Any of the cells produced by the early divisions of a fertilised animal egg
402
Zygote
The cell created by the union of two gametes, in which the gamete nuclei are also fused. The earliest stage of the diploid generation.
403
Embryo
A young animal while it is still contained within a protective structure such as an egg or uterus
404
Compaction
Event in early cleavage stage mammalian embryo during which blastomeres become tightly joined, forming gap junctions enabling the exchange of ions and small molecules to pass from one cell to the next. The formation of an epithelium, a morula.
405
Cadherin
Transmembrane protein group that plays important roles in cell adhesion, forming adheron junctions to bind cells within tissues.
406
Morula
A solid ball of cells resulting from division of a fertilised ovum, and from which a blastula is formed
407
Blastulation
The formation of a blastula from a morula
408
Blastula
An early stage of the animal embryo; in many species, a hollow sphere of cells surrounding a central cavity, the blastocoel.
409
Blastocyst
An early embryo formed by the first divisions of the fertilised egg (zygote). In mammals, a hollow ball of cells.
410
Blastocoel
The central, hollow cavity of a blastula
411
Blastodisc
An embryo that forms as a disc of cells on the surface of a large yolk mass; comparable to a blastula, but occurring in animals such as birds and reptiles, in which the massive yolk restricts cleavage.
412
Aerobic Glycolysis
The conversion of glucose to lactate in the presence of oxygen
413
Glycocalyx
A glycoprotein-polysaccharide covering that surrounds the cell membranes of some bacteria, epithelia and other cells. Most animal cells have a fuzz-like coat on the external surface of their plasma membrane
414
Decidua
The term for the uterine lining (endometrium) during pregnancy, which forms the maternal part of the placenta
415
Cytoplasmic Segregation
The asymmetrical distribution of cytoplasmic determinants in a developing animal embryo
416
Cytoplasmic Determinants
In animal development, gene products whose spatial distribution may determine such things as embryonic axes
417
B-catenin
A transcription factor produced from maternal mRNA
418
GSK-3
A protein kinase that phosphorylates and degrades B-catenin
419
Vegetal Hemisphere
The lower portion of some animal cells, zygotes and embryos, in which the dense nutrient yolk settles. The vegetal pole is to the very bottom of the egg or embryo
420
Animal hemisphere
The metabolically active upper portion of some animal eggs, zygotes and embryos; does not contain the dense nutrient yolk
421
Complete cleavage
Pattern of cleavage that occurs in eggs that have little yolk. Early cleavage furrows divide the egg completely and the blastomeres are of similar size.
422
Incomplete cleavage
A pattern of cleavage that occurs in many eggs that have a lot of yolk. Early cleavage furrows do not penetrate all of it.
423
Discoidal Cleavage
In animal development, a type of incomplete cleavage that is common in fishes, reptiles and birds. Results in a blastodisc
424
Superficial Cleavage
A variation of incomplete cleavage in which cycles of mitosis occur without cell division, producing a syncytium (a single cell with many nuclei).
425
Radial Cleavage
Cleavage where mitotic spindles form parallel or perpendicular to the animal-vegetal axis.
426
Spiral Cleavage
Cleavage where cell layers form at oblique angles to the animal-vegetal axis
427
Rotational cleavage
First cell division is parallel to the animal-vegetal axis, next division is at right angles: one parallel, the other perpendicular
428
Mosaic Development
Pattern of animal embryonic development in which each blastomere contributes a specific par of the adult body. If one blastomere is removed, the embryo will not form.
429
Regulative Development
A pattern of animal embryonic development in which the fates of the first blastomeres are not absolutely fixed. If a blastomere is removed, the embryo can still form.
430
Archenteron
The earliest primordial animal digestive tract.
431
Mesenchyme
Embryonic or unspecialised cells derived from the mesoderm.
432
Blastopore
The opening created by the invagination of the vegetal pole during gastrulation of animal embryos
433
Grey Crescent
In frog development, a band of diffusely pigmented cytoplasm on the side of the egg opposite the site of sperm entry. Arises as a result of cytoplasmic rearrangements that establish the anterior-posterior axis of the zygote.
