ch. 4 cell structure Flashcards
who discovered cells and when?
Hooke, 1660’s
who proposed the cell theory? when?
Schneider and Schwann, 1830’s
as a cell increases in size, volume increases ___x faster than the surface area
10
what three structures do all cells have in common?
genetic material, cytoplasm, plasma membrane
What is the function of prokaryotic cell walls?
they protect the cell and maintain cell shape
what are prokaryotic cell walls made of?
peptidoglycan (bacteria) or similar substances (archaea)
what does it mean if a prokaryotic cell wall is gram negative?
they are surrounded by a thin peptidoglycan cell wall which is surrounded by an outer-membrane
what does it mean if a prokaryotic cell wall is gram positive?
they lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negatives
where can you find simple flagella?
in some prokaryotic cells
what kind of motion does the simple flagella make to move the cell?
rotary motion
what surrounds the nucleus?
a nuclear envelope
what is the nuclear envelope composed of?
2 phospholipid bilayers
what is the function of ribosomes?
they are the site of protein synthesis
what are ribosomes composed of?
rRNA and proteins
where are ribosomes found?
in the cytoplasm and attached to membranes
what parts of the cell make up the endomembrane system?
nuclear membrane, ER, golgi, secretory vesicles
what is the endomembrane system?
a semi-continuous system of interconnected membranes
What are the functions of the rough ER?
creates a network of channels throughout the cytoplasm, synthesis of proteins that will be secreted and then sent to lysosomes or the plasma membrane
What are the functions of smooth ER
synthesis of membrane lipids, calcium storage, detoxification of foreign substances
what are the golgi apparatus?
flattened stacks of interconnected membranes that package and distribute materials to different parts of the cell and synthesize cell wall components
what do lysosomes contain?
digestive enzymes
what is the function of lysosomes?
they break down macromolecules for recycling of foreign matter that the cell has engulfed
what are microbodies?
vesicles containing enzymes
what are glyoxysomes?
microbodies in plants that contain enzymes for converting fats to carbs
what are peroxisomes?
microbodies that contain oxidative enzymes and catalase
are vacuoles membrane-bound?
yes
where can contractile vacuoles be found?
in some protists
what is the function of mitochondria?
they contain oxidative metabolism enzymes fir transferring energy from macromolecules to ATP
what do the two mitochondria membranes look like?
a smooth outer membrane and a folded inter membrane with layers called cristae
where is the matrix in the mitochondria?
within the inner membrane
what are thylakoids?
membrane sacs within the inner membrane
what is the cytoskeleton made up of
protein fibers
what is the purpose of the cytoskeleton?
supports the shape of the cell, keeps organelles in fixed locations, helps move materials within the cell
what are the three cytoskeleton fibers?
actin filaments, microtubules, and intermediate filaments
what are actin filaments responsible for?
cellular contractions, crawling, “pinching”
what is the purpose of microtubules?
to provide organization to the cell and move materials within the cell
what is the function of intermediate filaments?
they provide structural support
what makes up flagella and cilia?
microtubules
how is the cell movement “crawling” accomplished?
with actin filaments and myosin
what is the structure of cilia and flagella?
“9 + 2” structure
what is a “9 + 2” structure?
9 pairs of microtubules surrounded by two central microtubules
what drives the flagella and cilia?
proton gradients
what are some extra cellular structures?
cell walls and extra cellular matrix
what type of cells contain cell walls?
plants, fungi, and some protists
what is the CHO in the cell wall of plants and protists?
cellulose
what is the CHO in the cell walls of fungi?
chitin
what is chitin?
a glycoprotein
what is the extra cellular matrix composed of?
glycoproteins and fibrous proteins like collagen
how might the extracellular matrix be connected to the cytoplasm?
with integrin proteins present in the plasma membrane
how many cells do humans have?
over a trillion
what is endosymbiosis?
the theory that eukaryotic organelles evolved through a symbiotic relationship where one cell engulfed another (ex: mitochondria and chloroplasts)
