BIOLOGY: LIFE PROCESSES AT THE CELLULAR LEVEL Flashcards
Passive transport
the movement of particles across a plasma (cell) membrane from high to low concentration without using any energy
Diffusion
the net movement of particles from high concentration to low concentration
Facilitated diffusion
the movement of particles from high concentration to low concentration through a channel protein
Osmosis
the movement of water from high to low concentration through a semipermeable membrane
Channel proteins
proteins that create ‘pores’ in the cell membrane though which particles (eg Nat) diffuse
Carrier proteins
proteins in the cell membrane that change shape when particles (eg amino acids) bind to them, creating a channel for those particles to pass through
Flaccid
cells drooping due to a lack of water
Turgid
cells are swollen due to the cells containing a large amount of water
Plasmolysed
shrinking of the cytoplasm away from the cell wall in plant cells due to water flowing our of the cell by osmosis
Exocytosis
the movement of large molecules OUT of cells by the folding of membranes
Active transport
the movement of particles across a plasma membrane from low to high concentration using energy (ATP)
Cytosis
the movement of large molecules into or out of cells by the folding of membranes
Endocytosis
the movement of large molecules INTO cells by the folding of membranes
Pinocytosis
a type of cytosis where the cell takes up liquid material
Phagocytosis
a type of cytosis where the cell takes up solid material
Hypotonic solution
a solution that has a high concentration of water and a low concentration of solute
Isotonic
two solutions that have an equal concentration of water and an equal concentration of solute
Enzyme
a protein with a specific shape that acts as a biological catalyst
Hypertonic solution
a solution that has a low concentration of water and a high concentration of solute
Lysis
the destruction of a cell by the rupturing of its cell membrane
Active site
the part of the enzyme that binds to a substrate
Anabolic enzyme
one that forms larger molecules (eg proteins) from smaller ones (eg amino acids)
Activation energy
the minimum amount of energy the reacting species must possess to undergo a specific reaction
Catabolic enzyme
one that breaks larger molecules (eg starch) into smaller ones (eg glucose)
Denaturing
when the shape of the active site of an enzyme changes so it can no longer bind to the substrate
Co-factors
small molecules that bind into the active site of an enzyme and assist enzymes in catalysing a reaction
Lock and Key model
enzymes active site have a specific shape to which only one substrate can fit
Induced fit model
The active site of an enzyme changes shapes (ie is moulded) to fit a specific substrate
Co-enzymes
act as a bridge to lock the enzyme and substrate molecule together more tightly
Enzyme competitive inhibitors (poisons)
these are molecules that bind to the active site of an enzyme and prevent the substrate from binding
Metabolic pathway
A reaction that occurs over a series of small, enzyme controlled steps to produce an end product eg respiration
Enzyme non-competitive inhibitors (poisons)
bind to a part of the enzyme that is NOT the active site but causes the enzymes shape to distort so that the substrate can’t bind to the enzyme
Photosynthesis
the process by which plants make food (glucose)
Respiration
the process by which glucose is broken down to release ATP energy
Chromatin
a complex of DNA wound around histone proteins
Aerobic respiration
respiration with oxygen
Anaerobic respiration
respiration without oxygen
Chromosome
A single strand of DNA wound around histone proteins that contains many genes
DNA
a polymer of repeating nucleotides that makes up chromosomes
Nucleotide
the building blocks of DNA made of a nitrogenous base, deoxyribose sugar and a phosphate group
Complementary base pairing rule
A bonds with T and C bonds with G
Antiparallel nature of DNA
the two strands of DNA run in opposite directions to each other, one runs from 3’ (3 prime) to 5’ (5 prime) while the other strand runs from 5’ to 3’
Helicase enzyme
the enzyme that unwinds and unzips DNA strand
Leading strand
the DNA strand that is constructed as one continuous strand during DNA replication
DNA replication
making a copy of a DNA strand during cell division
Semi-conservative hypothesis
each new strand of DNA consists of one old strand and one new strand
Ligase enzyme
joins Okazaki fragments together during DNA replication
DNA polymerase enzyme
Binds complementary nucleotides to exposed strands of DNA during DNA replication
Lagging strand
the DNA strand that is formed in small fragments (Okazaki fragments) during DNA replication
Mitosis
the type of cell division that results in the formation of two identical daughter cells
Homologous pair of chromosomes
a pair of chromosomes that contain the same genes
Diploid number
the number of chromosomes found in a normal body cell
Haploid number
the number of chromosomes found in a gamete
Cell cycle
an orderly sequence of events that occurs from one cell division to the next.
Interphase
a part of the cell cycle where the cell carries out its designated function
