Cell Structures
It is the barrier between the outside world and the inside cell, regulates movement in/out of the cell, and is composed of a bilayer of phospholipids which have their fatty acid hydrophobic sides pointed at each other.
What is a plasma membrane?
Membrane bound sacs that store nutrients, waste, and other substances.
What is a vacuole?
Use of energy to move up a concentration gradient
What is active transport?
Typically unicellular, bacteria and archaebacteria, NO membrane bound organelles, NO nucleus
What is a prokaryote?
A neuron stimulates muscle contraction by sending signals across the neuromuscular junction, or the point of contact between a neuron and a muscle cell. The signaling process begins when membrane-bound structures inside the neuron fuse with the cell membrane, releasing signaling molecules into the neuromuscular junction. These molecules then diffuse through the junction and binds to receptors on the surface of the muscle cell, leading to muscle contraction.
Botulism is a rare illness caused by a toxin produced by the bacterium Clostridium botulinum. This toxin, called botulinum toxin, inhibits the process by which signaling molecules are released from neurons at the neuromuscular junction. This disrupts the neuron-muscle cell signaling pathway, resulting in temporary paralysis.
Based on the information above, which of the following cell processes does botulinum toxin most likely inhibit?
A) Facilitated diffusion through membrane channels
B) Membrane transport mediated by transmembrane ATPases
C) Vesicle Fusion during exocytosis
D) Receptor mediated endocytosis
C
A gel-like water based solution that contains ions, small molecules, and macromolecules (contains cytosol). This "organelle" provides structural support and shape for the whole cell.
What is a cytoplasm?
Contains genetic material and controls the activities of the cells, directs protein synthesis, and is composed of chromatin, nuclear membrane, nuclear pore, and the nucleolus.
What is the nucleus of the cell?
No use of energy to move down a concentration gradient
What is passive transport?
Has a nucleus and membrane bound organelles.
What is a eukaryotic cell?
One fatty acid has a straight structure and the other fatty acid has a kinked, or bent structure. Which of the following correctly describes how high levels of fatty acid structures contribute to the rigidity of the cell membrane?
A) The cell becomes less rigid as the amount of saturated fatty acids with a straight structure increase
B) The cell membrane becomes more rigid as the amount of unsaturated fatty acids with a straight structure increase
C) The cell membrane becomes more rigid as the amount of unsaturated fatty acids with a kinked structure increases.
D) The cell membrane becomes more rigid as the amount of saturated fatty acid tails with a straight structure increase.
D
Reasoning: Saturated fatty acids have hydrocarbon tails with a straight structure. A straight structure allows many saturated fatty acids to be densely packed together, which makes the cell membrane more rigid.
Provides structural strength and support, also semi-permeable surface for molecules to pass in and out of the cell. Also made of mostly polysaccharides (cellulose)
What is a cell wall?
A series of connected flattened sacs, a part of a continuous nuclear membrane organelle within the cytoplasm of eukaryotic cells, is involved with the production, folding, quality control of some proteins and hormones.
What is a rough endoplasmic reticulum?
cell eating
What is phagocytosis?
what is the reason why cells have to be small?
cells work better with a higher surface area to volume ratio (higher surface area means less volume).
Which of the following best explains how modified proteins are transported within a compartmentalized cell?
A) Modified proteins are transported within contiguous extracellular membranes that connect membrane-bound organelles
B) Modified proteins are transported in ribosomes that travel between membrane-bound organelles within the cell
C) Modified proteins are transported in vesicles that travel between membrane bound organelles within that cell
D) Modified proteins are transported within contiguous intracellular membranes that connect membrane-bound organelles.
C
Reasoning: A compartmentalized cell has membrane-bound organelles that function together through the use of vesicles. Vesicles transport modified proteins by budding off one organelle and then fusing with another organelle.
Made of proteins and RNA, uses ATP synthase to add an inorganic phosphate to run ADP into ATP (phosphorylation), and the site of protein synthesis.
What are ribosomes?
What is a smooth endoplasmic reticulum?
cell drinking
what is pinocytosis?
These are the three parts of cell theory
What is:
- All living things are made up of one or more cells
- cells are the basic unit of structure and function in living cells
- New cells are produced from existing cells
Gastric acid is a digestive fluid that is made with the help of parietal cells in the stomach lining. The parietal cell plasma membrane maintains a concentration gradient of potassium ions (K+K+start text, K, end text, start superscript, plus, end superscript) between the cell cytoplasm and the extracellular fluid. During the formation of gastric acid, K+K+start text, K, end text, start superscript, plus, end superscript moves down this gradient, passing from the cytoplasm into the extracellular space.
Which of the following is the most likely mechanism by which K+K+start text, K, end text, start superscript, plus, end superscript moves across the plasma membrane of a parietal cell during gastric acid formation?
A) K+ passes through membrane channel proteins.
B) K+ directly diffuses through the membrane bilayer.
C)K+ is transported through transmembrane ATPases.
D) K+ flows through aquaporins
A
Reasoning:
Membrane channel proteins facilitate the diffusion of charged and polar substances down their concentration gradients. K+ is charged and, according to the text, moves down its concentration gradient as it exits a parietal cell. So, it is likely that K+ moves across the parietal cell membrane by passing through membrane channel proteins.
A structure made up of microfilaments, actin filaments, and intermedieate filaments which are linked and held together to other organelles and the membranes by different proteins.
- makes up a cell's shape and organizes the cell's parts, keeping them in place
- helps in the formation of vacuoles and signaling- anchors organelles
What is a cytoskeleton?
Made of flattened pouches called cisternae and is near the ER and nucleus, lipids and proteins are recieved at CIS and is released at Trans Face.
Function: processes and packages proteins and lipids by folding them or adding more protein to them.
What is a golgi appatatus?
Used to move molecules that don't move easily- even when there is a gradient.
What is facilitated diffusion?
This is the theory of endosymbiosis
What is:
an early ancestor of eukaryotic cells englufed smaller prokaryotic cells?
A student uses a microscope to compare a human skeletal muscle cell and a human epithelial cell. The student observes that the muscle cell has more mitochondria than the epithelial cell.
Which of the following conclusions is best supported by this observation?
A) The epithelial cell does not require ATP to function
B) The muscle cell does not require ATP to function.
C) The muscle cell requires more ATP than the epithelial cell.
D) The epithelial cell requires more ATP than the muscle cell.
Answer: C
Reasoning: The main function of mitochondria is to produce ATP. The muscle cell has more mitochondria than the epithelial cell, so the muscle cell requires more ATP than the epithelial cell.