Chapter 3 - The Cell Flashcards
how big is a micrometer?
um (symbol), a unit of length equal to one millionth of a meter, or about the tenth the size of a droplet of fog/mist, or the size of an average mitochondrion (used to be referred to as a micron)
light microscopes
can see things the human eye cannot see, including most bacteria.
electron microscopes
can see a wide variety of the structures light microscopes can see, incl. viruses, ribosomes, all bacteria, proteins, lipids, and small molecules.
what is the least amount of cells an organism can have?
1
____ are the fundamental units of life.
cells
ALL cells on earth can be categorized into these two groups:
Prokaryotic and Eukaryotic
characteristics of prokaryotic cells
comprise single celled organisms, bacteria, and are very simple. cells may contain plasmids, pili, a capsule, and nucleoid.
characteristics of eukaryotic cells
larger, more complex cells, comprise single-celled or multicellular organisms, make up animals, fungi, plants, and protists
What are the two categories of prokaryotes?
Archaea and Bacteria
About how long have prokaryotes been around?
prokaryotic fossils date back 3.5 billion years
nucleoid
coiled DNA found in prokaryotic cells only unbound by any membrane
pili
short projections on the outside of prokaryotic cells, can attach to other prokaryotes
capsule
a sticky outer coat on prokaryotic cell walls, provides protection and helps the cell stick to surfaces
plasmids
small rings of DNA found in prokaryotes that duplicate independently and can be exchanged among cells
what structures do eukaryotic cells and prokaryotic cells have in common?
cytoplasm, cell wall, ribosomes, flagellum, plasma membrane
about how long ago did eukaryotic cells evolve from prokaryotic cells?
3 billion years ago
organelles are…
membrane-enclosed structures that perform specific functions
true or false: Prokaryotes contain organelles
False
what cell structures are unique to animal cells?
lysosomes
what are lysosomes?
membrane-enclosed bubbles of digestive enzymes (a type of vesicle) that break down and recycle foreign or worn-out cellular substances
what structures are unique to plant cells?
central vacuole, cell wall, chloroplasts
ribosomes
are free-floating or attached to the rough ER. They make protein that is necessary for usage in the cell.
mitochondria
where the cell harvests energy from food molecules and converts it into ATP
nucleus
location of much of a cell’s DNA
nuclear envelope
double layer of membrane that regulates transport of substances between the nucleus and cytoplasm
vesicle
membrane-enclosed sac that stores or transports materials in the cytoplasm
plasma membrane
outer boundary of the cell; regulates movement of substances going in an out of the cell
cytoskeleton
a network of fibers that provides support and aids movement
passive transport requires energy. (T or F)
False
active transport requires energy. (T or F)
True
passive transport involves the movement of substances along a concentration gradient from ___ to ___.
high to low.
active transport involves the movement of substances against a concentration gradient from ___ to ___.
low to high.
active transport moves AGAINST a concentration gradient. (T or F)
True
passive transport moves ALONG a concentration gradient. (T or F)
True
what is the word for the movement of molecules from an area of higher concentration to lower concentration?
Diffusion
osmosis
the diffusion of water
how does water diffuse?
from areas of high water concentration to low.
what are three types of passive transport?
diffusion, osmosis, and facilitated diffusion.
what is the process that helps larger molecules move through transport proteins?
facilitated diffusion
facilitated diffusion involves the transport of molecules from areas of lower concentration to high. (T or F)
False. Facilitated diffusion involves the transport of molecules from areas of high concentration to low.
how is active transport usually driven?
by a protein called a pump that sits within the membrane and quite a bit of energy
what are three methods of active transport?
exocytosis, protein pumps, and endocytosis.
exocytosis
export of large substances from the cell through fusion of vesicle membranes with the cell membrane.
(from: Greek “exo-“ meaning “outside”, Greek “kyto-“ meaning “receptacle, container, or body”, and “sis” (a Greek word used to form abstract nouns of action, process, state, condition, etc.)
endocytosis
the taking in of matter (usually large substances) by a living cell by the bending in of its membrane to form a vacuole.
what is the most prominent membrane-enclosed organelle?
the nucleus.
every eukaryotic cell contains a ____.
nucleus
Functions of the nucleus
1) stores most of the cell’s DNA in chromosomes 2) directs the activities of the cell
functions of the nuclear envelope
contains pores that allow only certain molecules to pass through.
structures of the nucleus
nuclear envelope (with a double membrane), nuclear pore, nucleolus, chromosomes
chromatin
fibers made of DNA molecules wrapped around proteins.
what are chromosomes made of?
each one is made out of a very long chromatin fiber twisted and folded a lot.
functions of DNA
DNA directs the processes of the cell by containing the instructions (RNA) used for protein production.
function of the nucleolus
the darker area within the nucleus, it produces ribosomes.
Name the organelles involved in the manufacture of proteins.
Endoplasmic Reticulum, ribosomes (floating or attached), & the golgi apparatus
what does RNA stand for?
ribonucleic acid
after transcription, RNA travels from the ____ to a ________.
nucleus, ribosome
The endoplasmic reticulum (ER) is made of lots of ______.
membranes
function of the smooth ER
produces lipids
function of the rough ER
CONTAINS ribosomes that PRODUCE proteins.
describe the location of the ER within the cell.
The ER is attached to the nuclear envelope, so it can pick up ribosomes easily and also act as a pipeline for ribosomes to enter the cytoplasm.
functions of the Golgi apparatus
the Golgi apparatus finishes, sorts, and ships cell products (including proteins) in vesicles. (the repackaging center)
functions of lysosomes
dissolve food molecules, old cellular components or organelles, or invasive organisms such as bacteria.
cell parts never wear out. (T or F)
FALSE
Name the organelles that provide energy for the cell.
chloroplasts and mitochondria
mitochondria are found in both plant and animal cells. (T or F)
True
what happens during photosynthesis?
the energy from sunlight is used to create molecules of sugar.
what do chloroplasts need to carry out photosynthesis?
water and carbon dioxide.
what are the products of photosynthesis?
sugar and oxygen.
What are the structures within the chloroplast?
an inner membrane and an outer membrane, stroma, thylakoids and stacks of thylakoids called grana (singular: granum)
thylakoid
flattened sacs inside a chloroplast, on whose pigmented membranes light reactions of photosynthesis occurs.
stroma
fluid within the inner membrane of the chlorplast
chloroplasts are to photosynthesis what mitochondria are to __________________.
cellular respiration
describe the process of cellular respiration
oxygen is used to harvest energy from molecules of sugar and produce cellular energy (ATP)
what is required for the mitochondrion to carry out cellular respiration?
sugar and oxygen
what are the products of cellular respiration?
carbon dioxide, water, and ATP
what are the structures of the mitochondrion?
internal fluid, outer membrane and inner membrane
what is the function of the mitochondrion’s inner membrane?
the inner membrane is highly folded and contains many of the enzymes needed for cellular respiration
what are vacuoles and what are some of their functions in the cell?
vacuoles are intracellular sacs that are used for storage (food, nutrients, pigments) and for pumping water out of a cell
what is the function of flagella?
they propel the cell with their whip-like movement. (think: sperm cells)
function of cilia
move in a coordinated back-and-forth motion.
Cilia on trachea cells help clear the airway.
what types of cells have a cell wall?
plant, fungus, and some prokaryotic cells.
what are cell walls made of?
cellulose fibers
cell walls are to plant cells what ________ are to animal cells.
cytoskeletons. Both maintain cell shape.
what are the functions of the cytoskeleton?
a network of protein fibers that provides mechanical support, anchorage, and reinforcement
each human body has how many chromosomes in the nucleus?
46
where does ribosomal RNA come from? What happens to it?
It is made in the nucleolus and exits through nuclear pores. It joins together with proteins to form ribosomes.
give an example of a situation that requires exocytosis
the exportation of tears in your tear glands
what is the most important function of membranes?
To regulate the flow of materials
What structure helps the cell maintain a relatively constant internal environment?
the plasma membrane
the liquid outside the cell is the __________ ________?
extracellular fluid
name the structures of the plasma membrane
phospholipid bilayer, carbohydrates, membrane proteins, extracellular fluid, cytoplasm
what is the purpose of carbohydrates on the plasma membrane?
carbohydrate chains extending from the plasma membrane serve as markers that other cells can recognize.
what are the various functions of membrane proteins?
regulation of passage of materials, aid in communication with neighboring cells, facilitation of enzymatic reactions, help anchoring the cell
the interior of the phospholipid bilayer is hydro_____ while the outside of the bilayer is hydro_____.
hydrophobic, hydrophilic
which parts of the bilayer are hydrophobic and hydrophilic, respectively?
phosphate heads are hydrophilic, fatty acid tails are hydrophobic. this allows them to spontaneously organize themselves.
why is the plasma membrane called a fluid mosaic?
molecules can move freely past each other allowing the membrane to flex and undulate, and because of the diversity of proteins amongst the phospholipids.
what makes up the cytoplasm?
watery liquid called cytosol, various organelles, and dissolved molecules
cholesterol function
a vital component of membranes that surround every cell in your body
extracellular matrix
a sticky substance produced by animal cells that helps hold them together
what are the reactants of photosynthesis?
water and C02
what are the products of photosynthesis?
oxygen and sugar
what are the reactants of cellular respiration?
oxygen and sugar
what are the products of cellular respiration?
water, C02, ATP
