Cell Functions Flashcards
Different Cells have different
Shapes depending on their function
The size of a cell is limited by its
Surface area-to-volume ratio
As a cell grow its volume
Increase much faster than its surface area
Cell Membrane (Plasma Membrane)
∙ Separates internal chemical reactions from external environment
∙ Regulates passage of material
∙ Made mostly of lipids & proteins
Cytoplasm
∙ Jelly-like liquid that fills the inside of cell
∙ Composed of water, salts, & proteins
∙ Median for chemical reactions
Nucleus (Nuclear Membrane)
∙ Filled w/ nucleoplasm & surrounded by a nuclear membrane
∙ Contains nearly all the cell’s DNA
∙ Site where DNA is transcribed into RNA
RNA
∙ Carries protein-building instructions to the ribosomes
∙ Travel to cytoplasm through pores in nuclear membrane
Chromatin (Chromosomes)
∙ When cell is diving the chromatin becomes a chromosome
∙ When not it remains as a threadlike material
Nucleolus
∙ Manufactures subunits that makeup ribosomes
Subunits
∙ 2 subunits: Large & Small
∙ Passes from nucleus - cytoplasm where they combine to form ribosomes
Ribosomes
∙ Found free-floating by cytoplasm or attached to ER
∙ Most numerous cell organelle
∙ Composed of protein & RNA & not membrane-bound
∙ Site of protein synthesis
Protein Synthesis
∙ Proteins assembled by ribosomes on rough ER
∙ Vesicles transport to GA & GA completes modifications
∙ Proteins are packaged in vesicles & leave GA
∙ Vesicle containing enzymes remain in cell as lysosomes
Endoplasmic Reticulum
∙ Functions as intercellular highway
∙ Rough ER - covered w/ attached ribosomes & makes proteins
∙ Smooth ER - no ribosomes & makes lipids
Golgi Apparatus
∙ Appears as stack of loosely connected membranes
∙ Function - modify, sort, & package protein that comes from ER
∙ Completes modifications before protein is shipped off
Vesicle
∙ Small, spherical stack surrounded by single membrane
∙ Classified according to content
∙ Types include - transport vehicles, lysosomes, & peroxisomes
Lysosomes
∙ From GA
∙ Filled w/ strong digestive enzymes & surrounded by think membrane
∙ Responsible for - destroying old organelles & destroying any debris that build up in the cell
Peroxisome
∙ Not from GA
∙ Break down alcohols, fatty acids, kills bacteria, & produce hydrogen peroxide
∙ Converts hydrogen peroxide to water & oxygen
Vacuole
∙ Storage area inside cell
∙ Stores water, salts, proteins, & carbohydrates
Mitochondria
∙ Purpose - cellular respiration
∙ Have own DNA, inner & outer membrane, & carry out own replication
∙ 100s/1000s may be found in cell
Cellular Respiration
∙ Process of converting glucose/sugar molecules into usable form of energy for cells
Cristae
∙ Increase surface area for respiration
Cytoskeleton
∙ Network of protein tubes & fibers that help cell maintain shape
∙Provides shape & support from inside
∙ 2 types of fibers: microfilament & microtubes
Microfilament
∙ Solid, threadlike, protein structures
∙ Helps cells move, bear mechanical stress, & give support
Microtube
∙ Functions - maintaining cell shape, separation of chromosomes during cell division, & formation of cilia & flagella
Centrioles
∙ 2 short cylinders at right angle to each other
∙ Found near nuclear membrane
∙ Organize microtubules during cell division to form framework for separating chromosomes