B1 + 2 Form and Function : Molecules Flashcards
Carbohydrates, lipids and proteins
macromolecules
A giant molecule created by atoms covalently bonded to one another.
lipids
Lipids are organic molecules. They are insoluble in water. They are found in the structure of cell membranes and used as energy stores.
disaccaride
Two monosaccharides chemically bonded together.
glycosidic bond
A covalent bond that connects a sugar molecule to another functional group, such as another sugar molecule or a protein. It is formed by a condensation reaction between hydroxyl groups,
polysaccaride
A major class of biomolecules, composed of long chains of carbohydrate molecules.
hydrolysis
A chemical reaction in which a water molecule is used to break down covalent bonds in a polymer to make monomers
Monosaccaride
The simplest form of a carbohydrate, consisting of a single sugar unit that cannot be broken down into smaller molecules by hydrolysis eg. glucose, fructose, galactose
isomers
Two or more compounds that have the same chemical formula but differ in the arrangement of atoms.
alpha glucose
isomer of glucose where the hydroxy group is facing down, contained in starch, is branched and helical
beta glucose
isomer of glucose where the hydroxy group is facing up, contained in cellulose, is unbranched and straight
oxidation
A chemical reaction that involves the loss of electrons from an atom or molecule.
reduction
A chemical reaction that involves the gain of electrons from an atom or molecule.
starch
The polysaccharide that serves as the main energy store in plants, there are two types - amylose (coiled) and amylopectin (branched and most common)
glycogen
A branched polysaccharide that serves as the primary energy storage molecule in humans stored mainly in liver and muscle cells
cellulose
A type of polysaccharide that is a major structural component of plant cell walls.
glycoproteins
A protein that contains one or more attached carbohydrates found on cell membranes that are involved in cell signalling and communication (also determines blood group).
triglycerides
A type of liquid molecule composed of three fatty acid chains attached to a glycerol.
amphipathic
A molecule or compound that has both hydrophobic and hydrophilic properties.
essential Amino acids
Amino acids that your body cannot produce.
genetic code
A set of rules that specifies how information stored in DNA is translated into the sequence of amino acids that make up proteins.
transcription
Process by which the genetic information encoded in DNA is copied into RNA.
translation
Process by which ribosomes use the genetic information carried by mRNA to synthesise proteins.
codon
A set of three adjacent nucleotides in DNA or mRNA that code for a particular amino acid.
degenerate
Refers to the redundancy in the genetic code, which allows for multiple codons to code for the same amino acid.
primary structure
Structure of a protein that refers to the specific sequence of amino acids that are joined together to form a polypeptide chain.
secondary structure
Structure of a protein that refers to the local folding patterns that occur within the polypeptide chain.
alpha helixes
A type of secondary protein structure that forms coils or helix with a right-hand twist.
beta pleated sheets
A type of secondary protein structure that forms pleats.
tertiary structure
Structure that gives rise to the overall three-dimensional shape of the protein.
disulfide covalent bonds
Covalent bonds that form between pairs of cysteine amino acid residues, which contain sulfur atoms.
hydrophobic interactions
The tendency of non-polar molecules to aggregate and repel water molecules.
myoglobin
A protein found in muscle tissue that binds and stores oxygen.
haemoglobin
The iron-containing protein present in red blood cells that carries oxygen.
globular proteins
Proteins that are compact and spherical in shape. They play important roles as enzymes, transporters and regulators.
quaternary structure
Structure of a protein refers to the arrangement and interaction of two or more polypeptide chains to form a functional protein.
conjugated protein
Proteins that contain a non-protein component such as a metal ion or a carbohydrate.
non-conjugated proteins
Proteins that consist only of amino acids linked together by peptide bonds.
fibrous proteins
Structural proteins that have an elongated shape.
collagen
A fibrous protein that provides strength and support to various tissues in the body, including bones, tendons and cartilage.
cholesterol
A type of lipid made in the liver that is found in all the cells of the body.
integral membrane proteins
Proteins that are embedded in the plasma membrane and cannot be easily extracted from the membrane.
peripheral proteins
Proteins that are attached to the plasma membrane that can be easily extracted.
channel proteins
Specialist proteins that facilitate the transport of water across cell membranes. Also known as aquaporins.
tetrameric proteins
A quaternary protein with four subunits.
endocytosis
A process by which cells take in molecules and particles from their environment by engulfing them into vesicles formed by the plasma membrane.
exocytosis
A type of active transport in which a cell releases materials into its exterior by fusing vesicles containing these molecules with the cell membrane.
voltage-gated channels
type of ion channels that are responsible for generating and transmitting information in the form of action potentials
ligand-gated channels
integral membrane proteins that contain a pore which allows the regulated flow of selected ions across the plasma membrane.
mechanically gated channels
specialized channels designed to respond to a spectrum of mechanical stimuli, including vibration, pressure, gravity and sound waves
CAM
(Cell-adhesion molecules) cell-surface proteins that help cells interact with each other or with their extracellular matrix.
cell junctions
Connections that allow cells to communicate with each other and its extracellular matrix, composed of several proteins.
tight junctions
A type of cell junction wherein adjacent cells form a tight barrier to regulate the movement of substances.
gap junctions
A type of cell junction wherein adjacent cells are linked together by intracellular channels.
Adhesive junctions
facilitate cell–cell adhesion in tissues to ensure structural stability and allow the cells to withstand mechanical stress present in epithelial cells and cardiac cells.
compartmentalisation
The organisation of different functions and processes within specific subcellular structures separated by plasma membranes.
lysosomes
Compartmentalised spaces within cells that are responsible for breaking down and recycling waste materials.
matrix
Enclosed region of the inner membrane of mitochondria containing enzymes and products for Krebs cycle.
cristae
Folds of the inner membrane of mitochondria, increasing the surface area for cellular respiration.
stroma
Space between the inner membrane and thylakoid membranes in chloroplasts containing enzymes and products for the Calvin cycle.
inter membrane space
Small space between the inner membrane and outer membrane of mitochondria.
thylakoid
The interior region of a thylakoid in chloroplasts, where the light-dependent reactions of photosynthesis occur.
granum
Stack of thylakoid membranes in plant chloroplasts that contain chlorophyll.
lamella
Structures that join granum.
nuclear pores
A complex structure that forms a channel through the nuclear membrane (double membrane surrounding the nucleus in eukaryotic cells) to regulate the transport of materials in and out of the nucleus.
blastocyst
A cluster of dividing cells formed by the fertilised egg during early embryonic development.
trophoblast
Cells that will become the placenta.
inner cell mass
Cells within the blastocyst that will become the embryo.
morphogens
A chemical in the cell the concentration gradient of which determines the fate of surrounding cells.
totipotent stem cells
Cells that have the ability to divide to generate the entire organism.
Pluripotent stem cells
Cells that can generate multiple types of cells of an organism.
multipotent stem cells
Cells that can generate many cells of an organism.
unipotent stem cells
Cells that can generate one cell type of an organism.
stem cell niche
The microenvironment within the organism in which the stem cells exist and receive their instructions.
type 1 pneumocytes
Very thin cells in the lung responsible for gas exchange.
type 2 pneumocytes
Cuboidal cells of the lung that secrete surfactant.
sarcomere
The basic contractile unit of a muscle, containing actin and myosin.
