3-1. Cells Flashcards
Cell Theory
All living organisms are made of cells
All cells come from previously existing cells
What are the two kinds of microscopes?
Light and electron microscope
Light microscope
Light passes through slide and glass to the eye
Magnifies up to 1000x
electron microscope
beam of electrons passes through objects, focused through magnifying lenses onto a screen
Magnifies up to 400,000x
What are the two types of electron microscopes?
scanning - 3d image of surface
transmission - inside section
Robert Hooke
First used the term cell to describe the little “room” he saw in tree bark
Schleiden and Schwann
Proposed that “all living things are composed as cells”, now known as the Cell Theory
Rudolf Virchow
made an addition to the cell theory: “all cells arise from previously existing cells”
What are the three things common to all cells?
plasma membrane
nucleus
cytoplasm
plasma membrane (structure)
aka “border patrol”
outermost membrane of all living cells; primarily made of two organic compounds: proteins and phospholipids
plasma membrane (function)
regulates passage of material in and out of cell - selectively permeable boundary
nucleus (structure)
aka “control center”
large, most obvious organelle in the cell
surrounded by a double membrane (nuclear envelope) with many holes (nuclear pores)
nucleus (function)
contains genetic information; directs all of the daily activities
Which two organic compounds make up the plasma membrane?
proteins and phospholipids
nucleoplasm
fluid inside nuclear envelope
nucleolus
dark spot visible during interphase (not dividing), where ribosomes are made
chromatin
long thin invisible strands of genetic material (DNA and protein) - present during interphase
chromasomes
chromatin coils into these visible bodies during mitosis
If chromasomes are visible, then the cell is in ___.
mitosis
if chromatin is not visible within the cell, then the cell is in ___.
interphase
Red blood cells are ___.
anucleate
Skeletal muscle cells are ___.
multinucleate
nuclear envelope
double membrane surrounding the cell’s nucleus
nuclear pores
holes in the nuclear envelope
cytoplasm
cellular material between plasma membrane and nuclear envelope
What are the two parts of cytoplasm?
cytosol and organelles
cytosol
viscous fluid inside cells; made primarily of water and some dissolved solutes
organelles
suspended in the cytosol; little organs are the metabolic machinery of the cell, each designed for a specific function
List the major cytoplasmic organelles.
ribosomes - protein factories
endoplasmic reticulum - pipeline
Golgi apparatus - UPS station/collecting and packaging
mitochondira - mighty mitochondira, power plant
lysosomes - digestive stations
ribosomes (function)
protein synthesis
ribosomes (structure)
tiny structures made of RNA and protein; may be found in endoplasmic reticulum or free in cytoplasm
endoplasmic reticulum (function)
movement of substances within cell; storage; protein synthesis (rough ER has attached ribosomes)
endoplasmic reticulum (structure)
complicated network of membrane channels curving through cytoplasm
What are the two types of endoplasmic reticulum
rough and smooth
rough endoplasmic reticulum
outer surface of the tubes is covered with ribosomes (appear granular); sites of protein synthesis
smooth endoplasmic reticulum
tubes without ribosomes; sites of lipid synthesis, drug detoxification, or mineral storage
Golgi apparatus (function)
molecules made in ER migrate here for storage, modification and packaging. Vesicles pinch off end, migrate to plasma membrane, fuse with it, and release contents outside of cell
Golgi apparatus (structure)
stacks of smooth flattened sacs resembling pancakes
mitochondria (function)
supplies the energy needed by cell, through a long series of chemical reactions in which carbohydrates are broken down
cellular respiration
C^6H^12O^6 + 6O^2 > 6CO^2 + 6H^2O + ATP
CO^2 and H^2O - waste
ATP - energy1
mitochondria (structure)
long, cylendrical bodies enclosed in a double membrane, inner membrane folded into many christae
Lysosomes (structure)
small membrane enclosed sacs in cytoplasm formed by budding from Golgi apparatus; contain digestive enzymes
Lysosomes (function)
sites of intracellular digestion:
- digests particles (eg. bacteria) taken in by endocytosis
- autophagy - breaking down damaged organelles (“cell eating”)
- autolysis - if a cell is badly injured, the lysosomes rupture and the cell self-destructs (eg. skin peeling from burn)
- break down bone to release calcium ions into the blood
autophagy
lysosomes breaking down damaged organelles (“cell eating”)
autolysis
if a cell is badly injured, lysosomes rupture and cell self destructs (eg. skin peeling from a burn)
Cell membranes are made of these two organic compounds
proteins and phospholipids
Phospholipids have ___ heads and ___ tails
hydrophilic heads; hydrophobic tails
When surrounded by water, phosophlipids: ___.
spontaneous form a bylayer, with heads facing water and tails hidden
Proteins are scattered through lipid bylayer, creating a ___.
mosaic pattern
integral proteins
firmly embedded; most act like open channels or act as carriers; others are receptors for hormones
peripheral proteins
loosly attached to one surface, usually inside
fluid mosaic model
all cell membranes are made of a bilayer of phospholipid molecules with protein molecules dispersed; the floating proteins form a constantly changing mosaic pattern
What are the four membrane functions?
- provides a flexible boundary enclosing the cell contents and separating it from the ECF and external environment
- facilitates contact between body cell (recognition and attraction)
- provides receptors for chemicals (hormones, antibodies, neurotransmitters)
- provides selective permeability allowing some substances to cross, while excluding others
