Unit 2 Cells Flashcards
What is the structure of a ribosome?
The structure of a ribosome consists of two subunits that are made of ribosomal RNAs and proteins. They can be found free floating in the cytosol or bound the the ER.
What is the function of a ribosome?
The function of a ribosome is the synthesis of proteins.
What is rRNA?
RNA molecules that combined with proteins create ribosomes. This is typically the most abundant form of RNA.
What is a protein?
A biologically functional structure made of one or more polypeptide folded and coiled into a 3D structure.
What is mRNA?
RNA that carries genetic information from DNA to the protein synthesizing machinery of the cell.
What is the function of the smooth endoplasmic reticulum?
Synthesis of lipids, metabolism of carbohydrates, storage of calcium ions, detoxification of drugs and poisons.
What is the function of the rough endoplasmic reticulum?
Helps with the synthesis or secretory of other proteins from bound ribosomes. It also adds carbohydrates to proteins, creating glycoproteins. It also helps produce a new membrane.
What is the structure of the ER?
It is a network of membrane bounded tubules and sacs. The membrane separates lumen from the cytosol. It is continuous with the nuclear envelope.
What are membrane bounded in ribosomes?
Ribosomes that are bounded to the membrane of the endoplasmic reticulum.
What is the structure of the Golgi complex?
It consists of flattened membranous sacs which have polarity due to having cis and trans faces.
What is the function of the Golgi complex?
It modifies proteins, carbohydrates on proteins, and phospholipids. It is helpful in the synthesis of many polysaccharides.it also helps sort Golgi products and then releases them in vesicles.
What is the function of the mitochondrion?
The mitochondrion helps with cellular respiration. It also helps with the transportation of electrons.
What is the structure of the mitochondrion?
It is bounded by a double membrane, and it has a folded inner membrane.
What is the Krebs cycle?
(Citric acid cycle) After glycosis the breakdown of glucose to carbon dioxide is completed.
What is the function of lysosomes?
The function of a lysosome to breakdown ingested substances, cell macromolecules, and damaged organelles for recycling.
What is the structure of lysosomes?
Membranous sac of hydrolytic enzymes.
What is apoptosis?
The programmed destruction or death of the cell.
What is the function of vacuoles?
They are large membrane bounded vesicles?
What is the structure of vacuoles?
They are large membrane bounded vesicles.
What is turgid pressure?
The force against a plant cell wall after large amounts of water and the swelling of the cell due to osmosis.
What is the function of the plasma membrane?
To control traffic entering and exiting the cell.
What is the structure of the plasma membrane?
Phospholipid bilayer lined with proteins and carbohydrates.
How do the hydrophobic and hydrophilic regions of the phospholipid bilayer work?
The hydrophobic fatty acid tails face each other in the interior of the bilayer. The hydrophilic phosphates point towards the external or internal aqueous environment.
What are thy e types of proteins in the plasma membrane?
Peripheral: attached to the inside or outside surface of the membrane. Integral: they are fully or partially embedded in the membrane. Transmembrane: they go all over he way through the membrane and allow polar/large molecules in or out of the cell. Glycoproteins: proteins with carbohydrates.
What are some other molecules that attach to the plasma membrane? (Not proteins)
Cholesterol, typically found with fatty acid tails. Carbohydrates, can be found forming glycoproteins or glycolipids .
What does selective permeability mean?
It allows biological membranes to control what substances enter and exit them.
How do large polar molecules and ions move through the membrane?
Through channel transport proteins.
How do polar uncharged molecules pass through the membrane?
They are let through in small amounts.
Describe the structure of the cell wall
Extracellular structure of plant cell wall after
Describe the function of the cell wall?
The cell wall protects plant cells from an excessive intake of water.
What is the function of chloroplasts?
They are the sites of photosynthesis. They are cells of photosynthetic eukaryotes.
What is the structure of chloroplasts?
They are typically made of two membranes that are around the fluid strokes which contains thylakoids stacked into grana.
What are thylakoids?
Thylakoids are flattened membranous sacs inside of chloroplast that exist in stacks known as grana. They convert light energy into chemical energy using molecular machinery.
What is the purpose of chlorophyll pigments?
They are a green pigment that participates in light reactions that convert solar energy into chemical energy
What is stroma?
The fluid surrounding the thylakoids membrane in chloroplasts. They contain ribosomes and dna. They are used in the synthesis of organic molecules from carbon dioxide and water.
What is carbon fixation?
The incorporation of carbon from CO2 into an organic compound of an autotrophic organism.
How do microvilli affect the surface area of a cell?
Microvilli increase the surface area of a cell; they are used for the exchange of materials with their surroundings.
How does the folding of inner membranes affect the surface area?
It increases the surface area
Explain how small cells and large cells differ in surface area to volume ratio?
Small cells have higher surface area to volume ratio.
Describe passive transport
The diffusion of a substance across a biological membrane without using energy. Is used in the import of materials and export of waste. Water can pass quickly through he cell with aquaporins but can’t without. High concentration to low concentration.
Describe active transport
The movement of a substance across a cell membrane against its concentration or electrochemical gradient. Low to high concentration. Needs input of metabolic energy. They establish and maintain concentration gradients.
Describe endocytosis
It is the cellular intake of biological molecules and some matter due to the formation of vesicles from the plasma membrane. It require energy to move large molecules into the cell.
Describe exocytosis
Cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane. It requires energy to move large macromolecules out of the cell.
What is facilitated diffusion?
Many polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane.
How do ions enter the membrane?
Through channel proteins. Membranes can become polarized by the movement of ions.
How does Na+/K+ATPase contribute to the membrane?
It contributes to the maintenance of the membrane potential.
What is osmosis?
The diffusion of water across a semipermeable membrane from high water concentration to low water concentrations
What is tonicity?
The way we describe how much solute is dissolved in the solvent.
What is a solute?
The substance that is being dissolved by the solvent
What is a solvent
A substance that does the dissolving of the solute
What is a hypotonic solution?
There is less solute and more water outside the cell, causing water to move inside the cell.
What is an isotonic solution?
Same solute, same solvent. No movement, equilibrium
What is a hypertonic solution?
There is more stuff and less water outside the cell. The water will move out of the cell.
Describe how water moves
From high concentration to low concentrations of water. Low solute to high solute.
What does it mean for a plant to be plasmolyzed?
Hypertonic, low water, sad
What does it mean for a plant to be flaccid?
Isotonic, okay
What does it mean for a plant to be turgid?
Hypotonic, filled with water, very happy
What is turgid pressure?
The pressure the water exerts back on the cell wall.
