Unit 4: Inside the Cell Flashcards
What four things do all cells have?
- Proteins
- Nucleic acids
- Carbohydrates
- Plasma membrane
Where are eukaryotic cells found?
Plants, animals, protists, and fungi
Where are prokaryotic cells found?
Bacteria and archaea
In prokaryotic cells, most bacterial and archaeal species have…
single, circular chromosome.
What are plasmids?
Prokaryotic cells may contain circular, supercoiled DNA molecules called plasmids.
How do the phospholipid components in prokaryotic cells differ?
(2 things)
- Bacterial phospholipids consist of fatty acids bound to glycerol.
- Archaeal phospholipids used branched isoprenoid chains bound to glycerol.
Prokaryotic DNA is _________. Why?
Prokaryotic DNA is Supercoiled to reduce the space and allow for much more DNA to be packaged.
What are internal photosynthetic membrane complexes in prokaryotic cells?
Multiple membranes passing through internal region of cell observed in photosynthetic bacteria.
What are organelles in bacteria?
Some bacteria have internal compartments called organelles.
What are the specialized tasks of organelles in bacteria?
- Store calcium ions.
- Hold magnetite crystals to serve as a compass.
- Concentrate enzymes to build organic compounds.
What are two external structures that enable movement and attachment in prokaryotic species?
- Flagella
- Fimbriae
What is a flagella?
Long filaments that
rotate to propel cell
What is a fimbriae?
Needlelike projections
that promote attachment to other
cells or surfaces
Eukaryotes can be ________ or ______.
Eukaryotes can be unicellular or multicellular.
What is the purpose of the specialized structure vacuole in plant cells?
- Digest and recycle macromolecules.
- Store water and ions.
What do vacuoles contain in seeds?
In seeds, they are filled with proteins
What do vacuoles contain in flower petals or fruits?
In flower petals or fruits, they contain pigments
What type of compound can vacuoles contain?
May contain noxious compounds to protect leaves and stems from
being eaten.
What are three specialized structures of plant cells?
- Vacuole
- Chloroplasts
- Cell Wall
What is the nucleus of a eukaryotic cell?
Large, highly organized membrane-bound compartment surrounded by double-membrane nuclear envelop.
What does the outside and inside surface of a nucleus in a eukaryotic cell look like? (2 things)
- Studded with pore-like openings.
- Inside surface is linked to the nuclear lamina
What is a nucleolus of a nucleus in a eukaryotic cell?
Location where ribosomal RNA is
synthesized and ribosome subunits are assembled
What are ribosomes in a eukaryotic cell?
Ribosomes are complex molecular machines that manufacture proteins.
Are ribosomes considered organelles?
No, they lack membrane—not considered
organelles.
Some ribosomes are free in the _______ or attached to ___________.
Some ribosomes are free in the cytosol or attached to endoplasmic reticulum.
Where do proteins go once they’re created in the ribosomes?
Manufacture proteins that remain in cytosol or are imported to other
organelles (e.g., nucleus).
What is the endoplasmic reticulum?
Extensive membrane-
enclosed factory that is
continuous with nuclear
envelope.
What are the two regions of the endoplasmic reticulum?
Two regions, distinct in
structure and function:
- Rough endoplasmic
reticulum (rough E R)
- Smooth endoplasmic
reticulum (smooth E R)
What is the Rough endoplasmic reticulum (rough E R)?
Studded with ribosomes: Dark, knobby-looking structures. Synthesizes proteins that are shipped to another organelle, inserted into plasma membrane, secreted to the cell exterior.
What is the smooth endoplasmic reticulum (smooth E R)?
Lacks ribosomes. Contains enzymes that catalyze reactions involving lipids.
As proteins are manufactured on
RER, they move to the _____.
lumen
What is a lumen?
The inside space where newly synthesized proteins fold and undergo modifications before being transported.
What happens to proteins in the lumen?
In RER lumen, proteins are folded and processed
Proteins made on RER may:
- Carry messages to other cells
- Act as membrane transporters or pumps
- Catalyze reactions
Most proteins that leave _____ must pass
through ___________.
Most proteins that leave RER must pass through Golgi apparatus
What is the purpose of the Golgi Apparatus?
Processes, sorts, and ships proteins
synthesized in rough E R.
How is the golgi apparatus formed?
Formed by series of stacked, flat, membranous sacs called cisternae.
What are the two sides of the cisternae?
- Cis (“on this side”) surface closest to
nucleus. - Trans (“across”) surface oriented
toward plasma membrane.
What is the purpose of cis?
Receives products from rough ER
What is the purpose of trans?
Ships them out to other organelles or cell surface
Where are lysosomes found?
Recycling centers found only in animal cells.
What is the purpose of lysosomes?
Enzymes specialized for hydrolyzing (breaking down) different macromolecules.
Digestive _______ inside lysosomes are
called _____________
Digestive enzymes inside lysosomes are called acid hydrolases
Where are peroxisomes found?
Globular organelles found in all eukaryotic cells.
Peroxisomes originate when empty vesicles from ER are loaded with _______________ from cytosol.
Peroxisomes originate when empty vesicles from ER
are loaded with peroxisome- specific enzymes from cytosol.
What are glyoxysomes?
Specialized plant peroxisomes, called
glyoxysomes, oxidize fats to form energy-storage compound.
Oxidation often produces ___________.
hydrogen peroxide
What is mitochondria in a eukaryotic cell structure?
Mitochondria supplies ATP to cells.
The mitochondria have two membranes:
- Outer membrane defines organelle’s surface.
- Inner membrane is folded into series of sac-like cristae.
The mitochondria are prone to ______ and ______.
The mitochondria are prone to fusion and fission.
What does fusion and fission result in for a mitochondria?
Elongated and
branched structures called mitochondrial networks or multiple
individual organelles.
Mitochondria have their own __________.
mitochondria DNA (mtDNA)
What are chloroplasts?
Most plant and algal cells have chloroplasts, where photosynthesis
takes place.
What are thylakoids in chloroplasts?
Have three membranes. Innermost membrane contains flattened sacs called thylakoids.
What is the grana of a thylakoids?
Thylakoids are arranged in stacks called grana.
What is the stroma of a thylakoids?
Surrounding the thylakoids is the
stroma (aqueous fluid).
How are mitochondria and chloroplasts similar?
Like mitochondria, chloroplasts contain their own DNA and manufacture their own ribosomes.
Chloroplasts ______ and _______ independently of cell division.
Chloroplasts grow and divide independently of cell division.
What is the endosymbiosis theory of where mitochondria and and chloroplasts came from?
Suggests that mitochondria and
chloroplast were once
free-living bacteria
What is the endosymbiosis theory of the relationship between bacteria and eukaryotes?
Bacteria were engulfed by ancestor of modern
eukaryotes but were
not destroyed.
What relationship evolved between eukaryotes and bacteria?
Mutually beneficial
relationship evolved
What functions does the nucleus perform pertaining to DNA and RNA? (2 things)
- Genetic information in DNA is decoded and processed.
- Large suites of enzymes interact to produce RNA messages.
________ functions as site of ribosome assembly.
Nucleolus
What is the structure of the nuclear envelope? (2 things)
- Separates nucleus from rest of cell.
- Perforated with openings called nuclear pore complexes.
What are nuclear pore complexes?
Allows Ribosomes, mRNA, proteins in and out of cell.
