Cell Structure and Function Flashcards
Definition of prokaryote
DNA of the cell is not separated from the cytoplasm
Definition of eukaryote
DNA is partitioned off in a membrane bound nucleus
Compare the characteristics of prokaryotic and eukaryotic cells
Properties of the plasma membrane
- Surrounds the cell
- Partially permeable
- Highly permeable to water and oxygen
- Charged ions do not pass through easily
Components of the cell membrane
- Phospholipids
- Protein
- Carbohydrates
Function of the protein component of the cell membrane
Pass ions into and out of the cell
Receptors
Structure of carbohydrate component of the cell membrane
Attached to proteins as glycoproteins or attached to lipids as glycolipids
Functions of carbohydrate molecules in cell membrane
Cell-cell recognition
Communication
Intercellular adhesion
Methods of transporting large molecules across plasma membrane
Exocytosis
Endocytosis (including pinocytosis and phagocytosis)
Define exocytosis
Release of material from the cell cytoplasm across the cell membrane
Define endocytosis
Uptake and transfer of molecules across the cell membrane into the cell interior
Define pinocytosis
Cells ingest small molecules of extracellular liquids
Define phagocytosis
Ingestion of large solid particles by the cells, e.g. bacteria
What is the endoplasmic reticulum?
A network of interconnected tubules & vesicles
What are the types of endoplasmic reticulum?
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Characteristics of the rough ER
Studded with ribosomes
Synthesizes proteins
Characteristics of smooth ER
Lacks ribosomes
Segregates newly synthesized proteins from the cytoplasm
Detoxification of drugs in the liver
Lipid synthesis (in gonads, adrenal gland)
Ca2+ reservoir in skeletal muscle
What are ribosomes formed from?
Made from 2 subunits formed from proteins
Where can ribosomes be found?
In the rough ER
Free in the cytoplasm
Functions of ribosomes
Translate mRNA into proteins
What are polyribosomes?
Clusters of ribosomes held together by strand of mRNA
What is the Golgi Apparatus?
Stacked and flattened membranous sacs which are closely associated with the rER
Shape of the Golgi Apparatus
Concave side (cis side): Near the ER
Convex side (tras side)
Function of the Golgi Apparatus
Modifies, packages and transports proteins and lipids secreted by the cells