Chapter 2 - Cell Structure, Cell Division, Transport Mechanisms Flashcards
Cells
All living things are composed of, discovered by Robert Hooke in 17th century
Composed of organelles
Most basic unit of life because a cell divides to reproduce itself
Plasma membrane
Outer boundary of the cell
DNA
Formation of genetic information in cells
Cytoplasm
Everything inside the plasma membrane, semi-solid substance
Fills space between plasma membrane and nucleus
Composed of organelles suspended in cytosol
Levels of organization
Organelles, cells, tissues, organs, systems
Organelles
Structure found inside a cell
Each performs a function necessary for a cell to survive and perform its duties
Tissues
Composed of identical cells
Four basic types in the body
Each type performs a specific function
Organs
Composed of two or more types of tissues
These work together to perform a specific function
Systems
Group of organs with related functions
Each system carries out one of the primary functions necessary to sustain life
Nucleus
Contains DNA
Pattern of building all proteins for the cell
Nuclear envelope
Membrane around nucleus
DNA cannot cross it
Nucleolus
Area in nucleus
Site of rRNA synthesis
Chromatin
Unwound DNA in nucleus
Nuclear pore
Opening in nuclear envelope
Allows mRNA out of nucleus
Cytoskeleton
Several different types
Internal scaffolding for cell
Plasma membrane
Outer boundary of cell
Lipid layer
Regulates what enters or leaves cell
Ribosomes
Composed of rRNA and proteins
Site of mRNA translation
Free ribosomes are in cytoplasm
Fixed ribosomes stud outside of RER
Rough endoplasmic reticulum (RER)
Membranous organelle
Network of channels
Site of protein synthesis
Mitochondria
Membranous organelle
Bean-shaped
Site of ATP synthesis
Lysosome
Membrane-bound vesicles
Contains digestive enzymes
Smooth endoplasmic reticulum (SER)
Membranous organelle
Forms tube-like structure
Site of lipid synthesis
Centriole
Paired organelle
Organizes spindle fibers during mitosis
Golgi apparatus
Membranous organelle
Forms stack of plates
Proteins packaged for secretion
Transport vehicle
Membrane-bound vesicle
Transports substances throughout the cell
Life cycle of a cell
Cell carries out its functions, grows to its full size, replicates its DNA and organelles then divides to produce two identical daughter cells
Mitosis
Division portion of the cell cycle
Ensure that each daughter cell receives the full and correct number of chromosomes from the parent
Equal division if DNA
Consists of four stages: prophase, metaphase, anaphase, telophase
Interphase
Consists of G1, S, & G2 phases
Time during which cell is carrying out its functions and growing larger
Replicates DNA as it prepares to divide
Cytokinesis
Division if cytoplasm
Results in two equal cells
Physician division of cell following division of DNA
When complete, two identifiable daughter cells are formed
Each daughter cell enters interphase and behinds the process again
Cell division
Consists of four the stages of mitosis and cytokineses
Time during which original cell produces two identifiable daughter cells
First growth (G1) phase
Cells grows larger
Carries out cellular functions
Synthesis (S) phase
DNA is replicated
Sister chromatids are formed
Organelles increase in number
Second growth (G2) phase
Cells grows larger
Prepares to divide
Continues to carry out cellular functions
Stages of mitosis
Cytokineses
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase (not a stage of mitosis)
Cell carries out its functions
DNA is diffuse and called chromatin
No chromosomes are visible
Cell replicates DNA and organelles as it prepares to enter mitosis
Prophase
First stage of mitosis
Chromatic condenses into visible chromosomes called sister chromatids
Sister chromatids are the result of DNA replication, two or more identified chromosomes connected by a centromere
Nuclear envelope behinds to break down
Spindle fibers appear
Metaphase
Second stage of mitosis
Nuclear envelope is gone
Centromere of each sister chromatid attaches to spindle fibers
Sister chromatids line up along equator of cell
Anaphase
Third stage of mitosis
Sister chromatids separate at centromere to produce individual chromosomes
Chromosomes begin to migrate to the poles
Telophase
Fourth stage of mitosis
Chromosomes reach poles
Spindle fibers disappear
Nuclei behind to reform
What is the universal solvent for biological solutions
Water
Organisms are roughly 75-85% water
What are some biological solutes that are dissolved in water
Sugars, proteins, electrolytes, and organic molecules
What is the plasma membrane composed of
Lipids causing it to be hydrophobic (hates water)
Becomes a selectively permeable barrier
Diffusion
Substances cross the membrane
Area of high concentration to low concentration
Passive process (no energy)
Simple diffusion
Molecules such as water, oxygen, steroid hormones are able to cross through the membrane freely
Facilitated diffusion
Molecules such as ions, glucose, and amino acid cannot move through independently
With the assistance of a channel or transport protein to cross the cell membrane
Unequal distribution of solute molecules
Solute particles are close together
Frequently collide with each other
Collisions give kinetic energy to solute molecules, causing them to spread out and become evenly distributed
Area of high concentration
Solute particles are close together
Frequently collide with each other
Area of low concentration
Few solute molecules
Plenty of room for molecules to move from area of high concentration to area of low concentration
Equal distribution of solute molecules
After time and many collisions
Solute molecules have spread evenly throughout solution
Osmosis
For it to occur there must be a selectively permeable membrane that is passable to the solvent (water in living bodies) but impassable to a solute
Water is freely passable and will diffuse from the side of lower solute concentration (hypotonic solution) toward the higher solute concentration (hypertonic solution) in attempt to reach equilibrium
If solution isotonic then there is no need for net movement
Hypotonic solution
Named for lower solute concentration
Hypo- means less than
Higher water (solvent) concentration
Net movement of water out of this side
Hypertonic solution
Named for higher solute concentration
Hyper- means greater than
Lower water (solvent) concentration
Net movement of water toward this side
Isotonic solution
ISO- means the same
Equal solute and solvent concentration on birth sides of the selectively permeable membrane
Water molecules continue to cross the membrane, but no further net movement
Selectively permeable membrane
Water, the solvent, freely passes through
Solute molecules cannot pass through
Osmotic pressure
Pressure generated within a cell as water presses against the plasma membrane
What will happen to blood in a isotonic solution
Equal solute concentration on both sides of the membrane
No concentration gradient
No net movement of water
No change in red blood cell (RBC) shape
What will happen to blood in a hypotonic solution
Smaller solute concentration outside of membrane
Concentration gradient exists
Net flow of water into RBC
RBC swells and may lyse (potentially burst)
What will happen to blood in a hypertonic solution
Greater solute concentration outside membrane
Concentration gradient exists
Net flow of water out of RBC
RBC crenates (shrinks)
