Exam 2 Flashcards
Anton von Leeuwenhoek
Was the first person to look at living things with a microscope. He was also an importer who looked at cloth fibers and wine.
Prokaryotic cells
Are bacteria, found in 3 shapes: bacillus, cocci, and spirillum.
They have a cell wall and some have a slime capsule, small free ribosomes, no nucleus.
Bacteria can either be gram + or gram -
Eukaryotic cells
Are plants, fungi, protists.
Ribosomes
Make proteins.
They are found in the cytoplasm and composed of ribosomal RNA.
Eukaryotes have relatively large ribosomes.
Prokaryotes or bacteria, mitochondria, and chloroplast have small ribosomes.
Smooth endoplasmic reticulum
Synthesizes lipids, and detoxifies drugs and alcohol.
What type of cell have a large amount of s.E.R.?
Stomach cells - produce large amounts of acid.
Testis, brain, and intestine cells produce and process hormones and fats.
Liver cells would detoxify drugs and alcohol.
Bone cells process calcium.
Rough endoplasmic reticulum
Looks rough because it has ribosomes on it’s surface. It is used to make proteins that are exported from the cell. Free ribosomes can become attached to it.
Signal sequence
Are found on proteins which are exported from the cell. The signal consists of a few amino acids before the actual protein starts.
The protein begins of a free ribosome. The signal and growing peptide attach to a recognition factor on the E.R. The signal and protein move to the E.R., and the ribosome docks or attaches to the E.R.
Golgi apparatus
Golgi are part of the endomembrane system.
They are found in cells that produce a lot of protein, such as grandular cells.
Golgi finishes folding and processing the protein. Proteins enter the cis face of the Golgi and exit from the trans face.
Lysosomes
Are membrane bound organelles that contain a variety of enzymes used to digest food and old organelles.
The enzyme works at a pH less than 7.
Microbodies or peroxisomes
Contain enzymes to convert H2O2 –> H2O and O2
Mitochondria
Convert glucose into ATP, release CO2, and are found in plants and animals.
A high concentration of hydrogen ion molecules build up in the outer compartment of the mitochondria because the inner membrane is not permeable to the hydrogen ions. Hydrogen ions can only escape through special pore proteins, and the outer membrane has a low permeability to hydrogen ions. This system has been maintained through evolution.
Chloroplasts
Take in CO2, use sunlight energy to make glucose and starch, and release O2. They are only found in plants.
Flagella
Have a 9 + 2 arrangement of microtubules.
Plasma membrane
Follows the fluid mosaic model.
Nuclear membrane
Is continuous with or connected to the endoplasmic reticulum. Nuclear pores are protein channels which allow selective movement out of the nucleus.
DNA never leaves the nucleus. DNA is packaged on histone proteins and form chromosomes, which are seen only at cell division. DNA that is active is uncoiled and called chromatin.
mRNA, tRNA, and rRNA are made in the nucleus and move out to the cytoplasm.
Proteins needed for nuclear activity may enter the nucleus.
Turgor pressure
Pressure on cell walls from water in the central vacuole or tonoplast. This pressure makes a plant stand tall.
Phagocytosis
The movement of food particles into a cell by wrapping it in a bit of membrane.
Pinocytosis
The movement of water into a cell by wrapping it in a bit of membrane.
Exocytosis
The movement of waste of products out of a cell by wrapping them in a bit of membrane, fusing the membrane with the cell membrane, and releasing the substance.
Contractile vacuole
A specialized vacuole found in protists. It collects excess water from inside a protist and then expels it to ensure that the protist doesn’t explode.
Active transport
Transport of materials into or out of a cell using protein pores and ATP. The sodium-potassium pump is an example.
Diffusion
The movement of particles from an area of high particle concentration to an area of lesser particle concentration.