Ch. 4-5 Test Flashcards
Describe the two parts of cell theory
- all living things are composed of cells
- all cells come from other cells
explain how cell size is limited
because the smaller it is, the easier it is for the cell to transport things in and out
describe the structure and functions of cell membranes
- Form a flexible boundary between the living cell and its surroundings.
- Regulate the entrance and exit of materials
compare and contrast prokaryotic and eukaryotic cells
- they both have a plasma membrane, DNA, ribosomes, and cytosol
-pro. are structurally simpler than euk. - eukaryotic cells have a membrane enclosed nucleus and many membrane enclosed organelles
(bacteria/archea-prokaryotic cells)(living things have-eukaryotic cells)
define cytosol
thick, jelly-like fluid on the inside of a cell from which cellular components are suspended
list every component of a prokaryotic cell and their function
fimbrae- sticking to other cells
flagella- movement
rod- shape
chromosomes- nucleoid
ribosomes- create proteins
plasma membrane- enclosing cytoplasm
capsule- outer coating, protection
nucleoid region- where DNA is located (not enclosed in membrane)
what are the 4 categories of organelles in eukaryotic cells
~ genetic control - nucleus and ribosomes
~manufacture, distribution, and breakdown of
molecules - endoplasmic reticulum, Golgi
apparatus, lysosomes, vacuoles, and
peroxisomes
~energy processing - mitochondria and
chloroplasts
~structure, movement, and communication -
cytoskeleton, plasma membrane, plant cell
wall
describe the nucleus
- houses the cells DNA and proteins (chromatin)
- surrounded by a nuclear envelope
- ribosomes are assembled in the nucleolus
describe ribosomes
- composed of ribosomal RNA and proteins
- synthesize proteins based on directions from
DNA - the more proteins a cell has = more ribosomes
- found free roaming or in rough ER
describe the Endoplasmic Reticulum
- a network of tubes and sacks
- Smooth ER synthesizes lipids and processes
toxins
- without ribosomes - Rough ER produces membranes, ribosomes on
its surface make membrane and secretory
proteins
- with ribosomes
describe the Golgi Apparatus
stacks of sacks where products of the ER are processed and sent to other parts of the cell
describe lysosomes
house enzymes that break down ingested substances and damaged organelles
describe vacuoles
large vesicles (huge shipping containers)
- some protists have contractile(pump)
- plants have a large central vacuole that stores
water, molecules, and waste
describe mitochondria
carry out cellular respiration in nearly all Eukaryotic cells
- intermembrane space
- matrix, contains DNA, ribosomes, and enzymes
that help in respiration
- has folds (cristae) that increases surface
area and helps create ATP
describe chloroplasts
photosynthesizing organelles of plants and algae
what organelles are found in only animal cells
- centrosome with centrioles
- lysosomes
what organelles are found in only plant cells
- cell wall
- plasmodesmata
- central vacuole
- chloroplasts
- the cytoskeleton includes ______
- list them from largest to smallest
- microfilaments
- intermediate filaments
- microtubules
what region do microtubules grow out of in an animal cell
the centrosome
where are centrioles located and what are their function
the centrosome, used in cell division
what locomotor appendages are made of microtubules
- in a 9 + 2 arrangement
- cilia (oars/rowing)
- flagella (whiplike motion)
what are the microfilaments, intermediate filaments, and microtubules functions
- maintain cell shape
- control movement of organelles
- amoeboid movement
- muscle contraction
where extracellular matrix found and what are its functions
- found in animal cells
- binds tissue cells together
- supports the plasma membrane
- communicates with the cytoskeleton
describe tight junctions
bind cells to form leak proof sheets
describe anchoring junctions
rivet cells into strong tissues
describe gap junctions
allow ions and small molecules to flow through a cell
describe the cell wall
- only in plants
- rigid
- protects and provides skeletal support
- mostly made of cellulose
describe plasmodesmata
- only in plant cells
- allow plant cells to share water, nourishment,
and chemical messages
define integrins
membrane proteins
describe the fluid mosaic structure of cell membranes
it is free moving and suspended in a liquid so it isn’t tied down
define selectively permeable
allows some substances to cross more easily than others
list the 6 types of membrane proteins
- transport proteins
- enzymes
- attachment proteins
- receptor proteins
- junction proteins
- glycoproteins
define transport proteins
allow specific ions or molecules to enter or exit the cell
define enzymes
some membranes proteins are enzymes; enzymes may be grouped to carry out sequential reactions
define attachment proteins
- attach to the extracellular matrix and
cytoskeleton - help support the membrane
- can coordinate external and internal changes
define receptor proteins
- signaling molecules bind to them
- relay messages by activating other molecules
inside the cell
define junction proteins
form intercellular junctions that attach adjacent
define glycoproteins
- serve as ID tags
- may be recognized by membrane proteins of
other cells
define diffusion
the tendency of particles to spread out evenly in an available space
describe passive transport
- diffusion across a membrane with no energy investment
- goes from an area of high concentration to low
define osmosis
the diffusion of water across a selectively permeable membrane
- requires no energy
- goes from high-low concentration
define tonicity
the ability of a surrounding solution to cause a cell to gain or lose water
- isotonic
- hypotonic
- hypertonic
describe isotonic
- concentration within the cell and outside the cell is equal
- gains water at the same rate it loses it
- remains the same size
describe hypotonic
- more water outside of the cell than inside
- the cell gains water, swells, and may burst(lyse)
describe hypertonic
- more water inside the cell than outside
- the cell shrivels and can die from water loss
define crenation
animal cells lose water and shrinks
define plasmolysis
plant cell loses water and cytoplasm shrinks
define cytolysis
when animal cells burst
define turgor pressure
water pressure within plants
- increased water -> increased pressure - plant stands
- decreased water -> decreased pressure - plant wilts
what materials freely move through the plasma membrane
carbon dioxide
water
oxygen
what materials need to be transported by carbon in the plasma membrane
macromolecules
charged molecules(ions)
describe facilitated diffusion
- doesn’t require energy
- relies on concentration gradient
define aquaporine
the very rapid diffusion of water into and out of certain cells (a protein channel)
define active transport
a cell must expand energy to move a solute against its concentration (low -> high)
what two mechanisms does a cell use to move large molecules across membranes
exocytosis and endocytosis
describe exocytosis
used to export bulky molecules, such as proteins and polysaccharides
describe endocytosis
used to take in large molecules
what are the three types of endocytosis
phagocytosis
pinocytosis
receptor-mediated endocytosis
describe phagocytosis
the engulfment of a particle by the cell wrapping cell membrane around it, forming a vacuole
describe pinocytosis
the engulfment of a liquid, utilizing the vesicle
describe receptor-mediated endocytosis
uses membrane receptors for specific solutions
define energy
the ability to do work
define kinetic energy
the energy of motion
define thermal energy
a type of kinetic energy associated with the random movement of atoms or
molecules.
define potential energy
is energy stored in the location or structure of matter and includes chemical energy
define chemical energy
the energy that’s stored in the bonds of chemical compounds
define the two laws of thermodynamics
- law of energy conservation
energy is constant
energy can be recycled but never created nor
destroyed - every energy conversion increases the entropy
of the universe
some entropy is lost as heat
define entropy
disorder or chaos
define endergonic and exergonic reactions
ex - release energy
ender - require energy and yield products rich in potential energy.
how do cells use energy coupling to survive
the use of energy released from exergonic reactions to drive endergonic reactions.
explain how enzymes speed up chemical reactions
they decrease the activation needed for a reaction to begin, without being consumed by the reaction
how are enzymes named
enzymes end in -ase (ex. lactose becomes lactase)
define substrate
the specific reactant that an enzyme acts on
define active site
the region of an enzyme that the substrate fits in
define induced fit
The active site changes shape slightly, embracing the substrate more snugly
what are the optimal conditions for enzymes to fucntion
temperature - high temp will denature the enzyme
pH - too acidic or basic can make the enzyme lose function
define denature
altering the protein’s specific shape and
destroying its function.
describe cofactors
nonprotein helpers, which bind to the active site and function in catalysis
define coenzymes
a cofactor that is an organic molecule
how do competitive inhibitors alter an enzymes activity
it reduces an enzymes productivity by blocking substrate molecules from entering the active site
how to noncompetitive inhibitors alter an enzymes acticity
doesn’t enter the active site. Instead, it binds to a site elsewhere on the enzyme, and its binding changes the enzymes shape so the active site no longer fits the substrate
how does feedback inhibition help regulate metabolism
it involves the use of a reaction product to regulate its own further production
