Chap 3 Cells Flashcards
What is a cell?
the smallest unit of life that can live independently
Is every living thing made up of cells?
yes, either one or more
What is used to view the entire cell?
light microscope
What is used to view the parts of a cell and viruses?
electron microscope
What are the common features among all cells?
genetic material
ribosomes
cytoplasm
cell membrane
What do ribosomes do?
produce proteins
What are prokaryotes?
small simple in structure and lack a nucleus
What are the domains of prokaryotes?
bacteria
archaea
What is the most ancient forms of life?
prokaryotes
What are eukaryotes?
larger more complex with many internal parts including a nucleus and other membrane bound organelles
What are the kingdoms of eukaryotes?
protists
fungi
plants
animals
What is free floating in the cytoplasm of a bacteria cell?
DNA
ribosomes
cytosol
What do animal cells have that bacteria cells don’t?
membrane bound organelles
Are bacteria prokaryotic or eukaryotic?
prokaryotic
Are animal cells prokaryotic or eukaryotic?
eukaryotic
Are plant cells prokaryotic or eukaryotic?
eukaryotic
What is different in a plant cell compared to an animal cell?
large central vacuole
cell wall
chloroplasts
What are the functions of the cell membrane?
forms a barrier b/w the cell and the outside world
regulates passage of substances in and out of the cell (maintaining homeostasis)
What makes up the cell membrane?
phospholipids
What is a phospholipid made of?
a molecule of glycerol, a phosphate group, and two fatty acids
What does amphipathic mean?
there are polar and nonpolar regions in the same molecule
Are phospholipids amphipathic?
yes
What is the structure of a phospholipid?
hydrophilic head
hydrophobic tail
What makes the head of a phospholipid hydrophilic?
polar bonds which are attracted to water
What makes the tail of a phospholipid hydrophobic?
nonpolar bonds which repels water
What is the structure of the cell membrane?
bilayer of phospholipids
When do phospholipids form a bilayer?
when surrounded by water
What is the function of a cell membrane?
to separate the cell from its surroundings
The phospholipid bilayer is selectively what?
permeable (to lipids and small nonpolar molecules)
What is embedded throughout the phospholipid bilayer?
proteins
What are the different functions of membrane proteins?
transport proteins enzymes recognition proteins adhesion proteins receptor proteins
Where are carbohydrates in/on the cell membrane?
protrude outward from the cell membrane
What is the function of carbohydrates in/on the cell membrane?
cell to cell communication
What else does the cell membrane contain?
steroids e.g. cholesterol
What is the function of the membrane steroids?
keep the membrane at the right level of fluidity (not too soft not too stiff)
What type of cell has a cell wall?
plant cells
Where is the cell wall located?
outside the cell membrane
What is the structure of the cell wall?
rigid wall of cellulose fibers
What are the functions of the cell wall?
impart shape
regulate cell volume
prevent bursting when cell take in too much water
What controls protein production?
the nucleus
Where is DNA located?
in the nucleus
What “specifies” the recipe fro proteins?
DNA
Other than DNA what else does the nucleus contain?
nucleolus
What is the function of the nucleolus?
synthesize ribosomes
Where is RNA synthesized?
nucleus
What is the purpose of Messenger RNA (mRNA)?
matches the sequence of DNA
What carries the “recipe” for making proteins?
mRNA
What is the copy of the genetic information?
mRNA
What does RNA bind to?
ribosomes (so protein synthesis can start)
Where are proteins synthesized?
on the ribosomes
What moves molecules around?
endomembrane system
What is the endomembrane made of?
nuclear envelope endoplasmic reticulum golgi apparatus lysosomes vacuoles cell membrane
Where to proteins go after synthesis?
rER (rough endoplasmic reticulum)
What happens to proteins in the rER?
they are modified and folded into their exact 3D shape
Where do proteins go after the rER?
the golgi apparatus
What moves the proteins from the rER to the golgi?
transport vesicles
What is the function of the golgi apparatus?
“processing center”
proteins are chemically modified to become functional
What is the structure of the golgi apparatus?
stack of membrane sacks
What happens to proteins when they leave the golgi apparatus?
sorted and packages into new transport vesicles
Which organelles are involved with cellular digestion?
Lysosomes
Vacuoles
Peroxisomes
Which organelles are involved with protein localization?
endomembrane system organelles
What do lysosomes contain?
hydrolytic enzymes
Where does cellular digestion of large molecules occur?
lysosomes
Do most plant cells have lysosomes?
No
Where does most cellular digestion in plants occur?
central vacuoles
Other than cellular digestion, what else do the central vacuoles do?
regulate the size and water balance of a cell
What breaks down toxic substances in a cell?
peroxisomes (also aid in digestion)
Where do peroxisomes originate and contain?
ER
enzymes that digest then oxidize certain toxic molecules
Which organelles are related to energy?
Mitochondria
Chloroplasts
Almost all eukaryotic cells have thousands of what?
mitochondria
How are mitochondria inherited?
maternally
What is the process that converts food energy to a form the cell can use for work?
cellular respiration
Where does cellular respiration take place?
mitochondria
From what do chloroplasts harvest energy?
light
What are the eukaryotes that use photosynthesis?
planst
some protists
What do chloroplasts do?
convert energy from sunlight into energy stored in sugar molecules
What is the cytoskeleton?
a network of protein tracks and tubules found in eukaryotic cells
What are the functions of the cytoskeleton?
structural support
aids in cell division
organelle transport
cell movement
What are able to move cells around?
cilia
flagella
What makes up the structure of cilia and flagella?
microtubules
Do cells need to communicate with each other to function properly?
yes
How do plant cells communicate?
plasmodesmata
What are plasmodesmata?
channels that pass through the plant cell wall
What travels through the plasmodesmata channels?
nutrients
biochemicals
How to animal cells communicate?
the stick together
What are the type of junctions between animal cells?
Tight
Anchoring
Gap
Describe a tight junction
from an impermeable barrier b/w cells
Describe an anchoring junction
attach cells to extracellular matrix (allows tissues to withstand mechanical stress)
Describe a gap junction
tunnels that ions and small molecules can pass through
Are each eukaryotic cell specialized?
yes