Unit 2: Cells Flashcards
What are the two types of cells?
Prokaryotes and eukaryotes
What are examples of prokaryotes?
Bacteria, archae, and extremophiles
What are examples of eukaryotes?
Plants, fungi, animals, protists
How are prokaryotes and eukaryotes different in terms of where DNA is located?
DNA is free floating in prokaryotes, located in the nucleus is eukaryotes
How are prokaryotes and eukaryotes different in terms of DNA shape?
Prokaryotes have circular DNA, eukaryotes have linear DNA
How are prokaryotes and eukaryotes different in terms of membrane bound organelles?
Prokaryotes have no membrane bound organelles while eukaryotes have membrane bound organelles
No membrane bound organelles
Prokaryotes
Membrane bound organelles
Eukaryotes
Circular DNA
Prokaryotes
Linear DNA
Eukaryotes
DNA is free flowing
Prokaryotes
DNA is located in the nucleus
Eukaryotes
What are some common structures between prokaryotes and eukaryotes?
Ribosomes, cell membrane, and cytoplasm
Liquid portion of the cytoplasm is called?
Cytosol
What are some synonyms for cell membrane?
Plasma membrane and phospholipid bilayer
What are the two types of ribosomes?
Free and bound ribosomes
Free ribosomes
Float freely in the cytoplasm and make proteins for inside the cell
Bound ribosomes
Attached to the rough ER and make proteins for outside the cell and the cell membrane
What is rRNA? How is it different from ribosomes?
rRNA is the RNA component of the ribosomes, which is a nucleic acid. The ribosomes organelles carry out protein synthesis.
Function of ribosomes
Protein synthesis
Nucleus function
Contains DNA
What is the nucleus surrounded by?
A nuclear envelope that separates the nucleus from the rest of the cell’s cytoplasm.
What does the nuclear envelope contain?
It contains small pores that allow for selective movement of molecules like RNA and proteins.
Function of endoplasmic reticulum (ER)
Intracellular (within the cell) transport
Rough ER has
Ribosomes
Smooth ER has
No ribosomes
What does rough ER do?
Makes proteins for cell membrane or to be taken out of the cell
What does smooth ER do?
Synthesizes lipids and steroids (estrogen, testosterone, cholesterol) and carries out detoxification
What are the four functions of the golgi apparatus?
- Sort and modify proteins and other macromolecules (complete protein synthesis)
- Make lysosomes
- Receive and make vesicles
- Export proteins out of the cell or to the cell membrane
Describe the endomembrane system
The nucleus uses mRNA to go to the rough ER. The rough ER synthesizes proteins. Proteins are then finalized by the golgi apparatus and exocytosed out of the cell with the help of vesicles.
Lysosome function
Digestive organelle
What process does the lysosome complete?
Hydrolysis (Breaking up a polymer into its monomers with the addition of water)
Apoptosis
Programmed cell death
Autophagy
Destroys warn-out cells
What is the significance of the endosymbiotic theory?
Marks the beginning of eukaryotes
What process does the mitochondria carry out?
Cell respiration to make ATP energy
Mitochondria has its…
Own ribosomes and circular DNA (related to prokaryotes)
Explain the endosymbiotic theory?
Mitochondria was engulfed by a prokaryotic cell and wasn’t digested. Since you can’t have organelles in prokaryotes, this was the beginning of eukaryotes.
Vacuole function
Stores food, water, and waste
What covers the vacuole?
A membrane called the tonoplast surrounds the vacuole. It basically separates the vacuole’s contents from the rest of the cell’s cytoplasm.
What is surface area?
The sum of the areas of all faces on a 3-D object
Describe surface area to volume ratio using words
Amount of surface area in a given volume
How do cells increase their surface area?
By folding (think about YouTube video with guy cutting paper) and cilia
Why is a large surface area to volume ratio a good thing for cells?
Nutrients and wastes diffuse faster and more efficiently
How does cilia help increase surface area?
The tiny finger-like structures extending outward from the cell membrane increase the cell’s exposed surface area
What are some structural adaptations that help increase surface area to volume ratios?
Root hairs of plants help to absorb nutrients and water
Structural adaptations of desert hares (ears, legs)
- Large, thin ears that allow for the evaporation of water and cool down body temperature
- Longer legs, meaning there is more surface area exposed to cool the body down
Structural adaptions of snow shoe hares (ears, legs)
- Smaller ears with more hair that keep heat in and there’s less exposed surface area
- Shorter legs with less surface area exposed to help keep in heat
How do cells achieve the optimal SA:V ratio?
Small, lots of folds, and containing organelles increase the effective surface area for cellular processes within a given volume
What does the cell membrane do?
Regulates what comes in and out of the cell
The cell membrane is
Semi permeable
The “head” portion of the phospholipid bilayer is:
Polar, hydrophilic
The “tail” portion of the phospholipid bilayer is:
Nonpolar, hydrophobic
If there is a protein partially touching the inside of the cell membrane and a part sticking out of the cell…
Part touching is nonpolar, part that’s out and not touching anything is polar
The cell membrane regulates what comes into and out of the cell based on…
Size, charge, and polarity
Why is it called a bilayer?
You need two sets of hydrophobic tails and hydrophilic heads in order to have water inside
Example the fluid mosaic model of the cell membrane
Molecules move laterally throughout the membrane, which behaves like a fluid
Cell membrane with a high concentration of saturated fats:
Stiff (s), rigid
Cell membrane with a low concentration of saturated fats:
Loose (l)
What kinds of molecules can easily pass through the nonpolar region of the cell membrane with no resistance?
Nonpolar, no charge, small
Examples of molecules that can pass through the nonpolar part of the cell membrane with no resistance
Oxygen, carbon dioxide
What kinds of molecules cannot easily pass through the nonpolar region of the cell membrane with no resistance?
Polar, charged, large
How is cholesterol represented in the cell membrane?
Triangles
What does cholesterol do in the cell membrane?
Maintains fluidity of the membrane
Integral proteins
Transport things to go into the cell membrane
What’s an example of an integral protein?
Aquaporins
What do aquaporins do?
Transport water
If the aquaporin is denatured, what would happen?
Water will still enter the cell, but not as much
Peripheral proteins
Used for cell signaling and immune response
What do peripheral proteins look like?
Gumdrops
Glycoproteins or glycolipids
Cell recognition and immune response
What do glycoproteins or glycolipids look like?
Gumdrop with lots of smaller dots/circles attached to it
Enzymes =
Proteins
Golgi appartus does what in regards to tertiary structure?
Finalizes proteins’ tertiary structure (completes the folding)
Advantage of organelles? (4)
- Larger sized cell
- Compartmentalize reactions
- More metabolic reactions
- Increase complexity of an organism
Cytoskeleton
Gives cells their shape and structure
mRNA
Nucleus copies DNA into a smaller mRNA form which goes to he rough ER