unit 1 aos 1 Flashcards
chapter 3
passive transport
the movement of molecules through a semipermeable membrane and down the concentration gradient, without an input of energy
active transport
movement of molecules across a semipermeable membrane that requires energy
diffusion
the passive movement of molecules from areas of
high concentration to areas of low concentration (down the concentration gradient)
concentration gradient
the difference in solute concentration between two adjacent areas
solute
a substance dissolved in the solvent
solvent
liquid in which a solute is dissolved, forming a solution
nonpolar
describes a molecule without a clearly positive or negative end. These tend to
be hydrophobic
polar
describes a molecule with both a positive end and a negative end. These tend to be hydrophilic
facilitated diffusion
a type of passive transport where molecules move through a phospholipid bilayer with
the aid of a membrane protein
protein channel
a transmembrane protein pore in a phospholipid bilayer that selectively enables transport of large or polar molecules
carrier protein
a membrane protein that undergoes conformational change to transport molecules across a membrane
osmosis
the passive transport of a solvent (typically water) through a semipermeable membrane
from a region of high water concentration, low solute (high solvent) to a region of high solute (low solvent), to a region of low water concentration.
hypertonic
describes a solution with a higher solute concentration when compared to another solution
isotonic
describes a solution with the same solute concentration as another solution
hypotonic
describes a solution with a lower solute concentration when compared to another solution
exocytosis
a type of bulk transport that moves large substances out of the cell
endocytosis
a type of bulk transport that moves large substances into the cell
surface area : volume ratio (SA:V)
a comparison of the amount of surface area per unit of volume. In Biology, SA:V influences temperature regulation, and a
high SA:V leads to more effective transport into and out of cells
simple diffusion
the diffusion of solutes across the plasma membrane.
homeostasis
homeostasis is the body’s ability to maintain a stable internal environment within a narrow range, despite changes to the external environment.
cell theory
cell theory the idea that all living things are made of cells, cells are the smallest functional unit of living things, and all cells come from pre-existing cells
prokaryotes
prokaryotes a group of single-celled organisms with no nucleus and a circular loop of DNA. Bacteria and archaea are both prokaryotic
eukaryotes
eukaryotes a group of single and multi-celled organisms with a nucleus and linear strands of DNA. Animals, plants, fungi, and protists are eukaryotic
plasma membrane
the phospholipid bilayer and embedded proteins which separate the intracellular environment from the extracellular environment.Also known as cell membrane
cytosol
cytosol the aqueous fluid that surrounds the organelles inside a cell
membrane-bound organelle
membrane-bound organelle
structure within a cell that is enclosed by a phospholipid bilayer
chromosome
chromosome the structure made of protein and nucleic acids that carries genetic information
somatic cell
somatic cell any cell that is not a reproductive cell (such as sperm and egg cells). Somatic cells are diploid (2n), meaning they contain two sets of chromosomes – one inherited from each parent
mitosis
the cell division phase which involves the complete separation of sister chromatids and nuclei
germline cells
germline cells cells that are involved in the generation of gametes in eukaryotes
gametes reproductive
cells that arise from germline cells that contain half the genetic material (n) of a somatic cell. In humans, gametes are sperm and eggs
meiosis
a specialised form of cell division used to produce gametes in sexually-reproducing organisms
binary fission
the method of cell replication used by prokaryotes
red blood cells
cells that transport oxygen through the bloodstream and do not contain a nucleus
surface area : volume ratio
surface area : volume ratio (SA:V) a comparison of the amount of surface area per unit of volume. In Biology, SA:V influences temperature regulation, and a
high SA:V leads to more effective transport into and out of cells
selective permeability
a property of cell membranes that ensures only specific substances pass across them. Also known as semipermeable
phospholipid
phospholipid the main molecule of which membranes are composed. They have a phosphate head and two fatty acid tails
phospholipid bilayer
a double layer of amphiphilic molecules that forms the primary component of cell membranes
phosphate head
the hydrophilic subunit of a phospholipid-polar
fatty acid tail
the hydrophobic lipid subunit of a phospholipid- non-polar
hydrophilic
having a tendency to be attracted to and dissolve in water
polar
polar describes a molecule with both a positive end and negative end. These tend to be hydrophilic
hydrophobic
hydrophobic having a tendency to repel and be insoluble in water
nonpolar
nonpolar describes a molecule without a clearly positive or negative end. These tend to
be hydrophobic
amphipathic
amphipathic describes molecules with both hydrophilic and hydrophobic components.
Also known as amphiphilic
integral protein
integral protein a protein that is permanently secured to the plasma membrane
transmembrane protein
transmembrane protein an integral protein that spans the entire plasma membrane
peripheral protein
peripheral protein a protein that is temporarily attached to the plasma membrane
cytoskeleton
cytoskeleton the microscopic web of protein filaments in the cytoplasm. It provides structure and support, and transports products around the cell
glycolipid
glycolipid a phospholipid bound to a carbohydrate
glycoprotein
glycoprotein a protein bound to a carbohydrate
tonicity
a measure of the relative concentration of solutes on either side of a semipermeable membrane, described as hypertonic, hypotonic, or isotonic
turgid
turgid describes plant cells that are swollen and firm from water uptake
bulk transport
bulk transport a type of active transport that uses vesicles to move large molecules or groups of molecules into or out of the cell. Also known as cytosis
vesicle
vesicle a small membrane-bound sac that transports or stores substances within a cell
exocytosis
exocytosis a type of bulk transport that moves large substances out of the cell
endocytosis
endocytosis a type of bulk transport that moves large substances into the cell
phagocytosis
endocytosis of solid
material or food particles
pinocytosis
pinocytosis endocytosis of liquid or dissolved substances
binary fission
the method of cell replication used by prokaryotes
steps of binary fission
-The circular chromosome is uncoiled and the DNA is replicated. Plasmids also replicate.
- the cell elongates as it prepares to separate into two new cells and the duplicated circular chromosomes migrate to opposite ends
-cell then begins to undergo cytokinesis – the process of separating into two new cells – by pinching inwards and creating a septum.
-A new cell wall and membrane are formed down the centre of the cell.
-two new genetically identical cells are formed
plasmid
a small, circular loop of DNA that is separate from a chromosome, typically found in bacteria
cytokinesis
cytokinesis the division of the cytoplasm and formation of two daughter cells
septum
septum a dividing wall formed during binary fission
interphase
interphase the first stage of the eukaryotic cell cycle which involves cellular growth and duplication of chromosomes. Composed of three phases: G1, S, and G2
chromosome
chromosome a structure composed of DNA tightly wrapped around histone proteins. Carries the genetic information (genes)
of a cell
chromatid
chromatid one half of a double- stranded chromosome
centromere
centromere the structure which holds sister chromatids together
apoptosis
apoptosis the controlled death of cells in the body. Also known as programmed cell death
stem cell
undifferentiated
cells with the capability of differentiating into specialised cells
differentiation
differentiation the development of a stem cell into a specialised cell with a particular function
specialised cells
which serve a unique, particular function
