Biology Mid-term** Flashcards
What are cell organelles?
Small organs that carry out all the functions of a cell.
What is the cell membrane?
Structure that separates the cell interior from the outside world and controls the movements of materials into and out of the cell.
Helps the cell maintain homeostasis and has a phospholipid bilayer.
What is the cell wall?
Surrounds the cell membrane and is strong and fairly rigid.
It helps to give a plant shape and support and is made up of a network of tough fibers mainly made of cellulose.
What is cytoplasm?
Everything inside the cell membrane including the organelles (except the nucleus).
What is cytosol?
The fluid inside the cell in which the organelles are suspended.
What is the nucleus?
Command center of the cell that contains DNA blueprints for making proteins.
Surrounded by a double membrane to protect the DNA.
What is the nucleolus?
A specialized area of chromatin inside the nucleus responsible for producing ribosomes.
What are ribosomes?
Tiny two-part structures found throughout the cytoplasm that help put together proteins.
What is the endoplasmic reticulum (ER)?
A system of a flattened membrane-bound sac and tubes continuous with the outer membrane of the nuclear envelope.
What is rough endoplasmic reticulum?
Has ribosomes and synthesizes protein.
What is smooth endoplasmic reticulum?
Has canals which help transport the proteins throughout the cell.
What are vesicles?
Small membrane-bound transport sacs.
Some special types of vesicles have different jobs in the cell.
What is a lysosome?
Contains digestive enzymes that break down old cell parts or materials brought into cells.
What is the Golgi apparatus?
Stack of flattened membrane-bound sacks that receive vesicles from the endoplasmic reticulum.
It packages finished products in the vesicles for transport to the cell membrane (for secretion out of the cell) and within the cell as lysosomes.
What is a vacuole?
Large membrane-bound fluid-filled sac for the temporary storage of food, water, or waste products.
What is a mitochondrion?
Powerhouse of the cell where organic molecules (usually carbohydrates) are broken down inside a double membrane to release and transfer energy.
What is a chloroplast?
Site of photosynthesis.
It gives green plants their color and transfers energy from sunlight into stored energy and carbohydrates during photosynthesis.
How do the cells work?
Insulin protein information from DNA is copied to RNA. RNA exits the nucleus. At ribosomes on the surface of rough ER, information from RNA is used to make a protein that will become insulin. Vesicles from smooth ER package the protein for transport to the Golgi apparatus. In the Golgi apparatus, the proteins are processed to form insulin protein and packaged for export out of the cell. Insulin is released from the cell when vesicles fuse with the cell membrane.
What are the organelles for the sheet?
Lysosome, nucleolus, nucleus, Golgi apparatus, endoplasmic reticulum, cell membrane, ribosome, cytoplasm, mitochondria.
What are the types of cells?
Prokaryotic and eukaryotic.
What is a prokaryotic cell?
Have no nucleus, simple internal structure, move using flagella, have cell walls made of a chemical called peptidoglycan, and lack membrane-bound organelles.
What is a eukaryotic cell?
Have a nucleus, have membrane-bound organelles, and are bigger than prokaryotic cells.
What are the differences between plant cells and animal cells?
Plant cells have an outer cell wall made of cellulose; animal cells do not. Plant cells have one large vacuole; animal cells have several small ones. Plant cells have chloroplasts; animal cells do not.
What does the cell membrane do?
Transports raw material INTO the cell, transports manufactured products and waste OUT of the cell, prevents the entry of unwanted material into the cell, and prevents the escape of matter needed to perform cellular functions.
Has a phospholipid bilayer.
The cell membrane is _______ and that means…
Selectively permeable.
That means it allows some molecules to enter the cell and prevents others.
What is the phospholipid bilayer?
Composed of a hydrophilic head and two hydrophobic tails.
What is cholesterol?
A lipid that regulates the rigidity of the membrane over different temperature ranges.
What are carrier proteins?
Change shape to move specific molecules in or out of the cell.
What are channel proteins?
Have a tunnel that allows specific ions to move in or out of the cell.
What are proteins in the cell membrane?
Serve to allow materials in and out of the cell.
These proteins are often specific to certain molecules.
What are carbohydrates in the cell membrane?
Attach to proteins or phospholipids and protrude outside the cell.
Often involved in the immune response, helping cells to identify one another.
What are the two main methods of maintaining homeostasis?
- Passive transport 2. Active transport.
What is passive transport?
The movement of any substances across a cell membrane without the use of cellular energy.
What are the 3 types of passive transport?
- Simple diffusion 2. Osmosis 3. Facilitated diffusion.
What is simple diffusion?
The movement of molecules from a region of higher concentration to lower concentration.
Occurs down the concentration gradient (high to low).
What is osmosis?
The diffusion of water molecules across a selectively permeable membrane.
What is facilitated diffusion?
If materials are too large or too charged to diffuse across the membrane without assistance, channel or carrier proteins provide help to move them.
The integral proteins are specific to the materials they are transporting by size, shape, and electric charge.
What are the 3 different types of extracellular solutions?
- Isotonic 2. Hypotonic 3. Hypertonic.
What is an isotonic solution?
Water concentration outside the cell is equal to the concentration inside the cell.
Water is moving in and out of the cell equally.
What is a hypotonic solution?
Water concentration outside the cell is greater than the concentration inside the cell.
Water moves into the cell.
What is a hypertonic solution?
Water concentration outside the cell is less than the concentration inside the cell.
Water moves outside the cell.
What is tonicity in animal cells?
Hypotonic solution = cytolysis (too much water inside the cell can cause it to explode). Isotonic solution = normal (proper flow of water in and out of the cell). Hypertonic solution = shriveled (cell isn’t getting enough water and shrivels up).
What is tonicity in plant cells?
Hypotonic solution = turgid (normal). Isotonic solution = flaccid. Hypertonic solution = plasmolysis (shriveled).
What is active transport?
The movement of any substance across a cell membrane with the use of energy from ATP.
PROTEINS move substances from areas of lower concentration to areas with higher concentration (against the concentration gradient).