CH3 Flashcards
Cell
The basic living thing, structural and functional unit of the body
Cell Biology
Or Cytology: study of cell structure
Parts of a cell
1) Plasma membrane
2) Cytoplasm
- Cytosol
- Organelles (except nucleus)
3) Nucleus
- Chromosomes
- Genes
Plasma Membrane
- Flexible, sturdy phospholipid bilayer barrier that surrounds and contains the cytoplasm. Seperates internal from external environment
- Selectively permeable
- Made up of:
+ Phospholipids - non-polar tails, polar heads, Cholesterol - helps to stabilize membrane and Proteins
Polar
Head, hydrophilic
Nonpolar
Tail, hydrophoboic. Points towards center of bilayer
Integral Proteins
Extend into or across entire lipid bilayer
- Transmembrane proteins
Peripheral Proteins
Found at the inner or outer surface of membrane
- Can be stripped away without damaging membrane
Concentration Gradient
Difference in concentration of a chemical b/w one side of plasma membrane and the other
Electrical Gradient
Difference in concentration of ions b/w one side and the other
Concentration + Electrical gradients
Make up electrochemical gradient
- O2 and NaCl are concentrated outside the cell
- Carbon dioxide and potassium ions are concentrated inside the cell
+ Inner surface negatively charged, outer surface positively charge
Diffusion
Net movement of molecules from an area of high concentration to low concentrations, like osmosis
Factors that affect rate of diffusion
Steepness of concentration gradient, temperature, mass, surface area, and distance of diffusion
Steepness
Diffusion will continue until the gradient is equalized and the concentrations are equal
Temperature
Higher temp will diffuse faster
Mass
Heavier will move slower, lighter moves faster
Surface Area
Surface area of membrane increases, the rate of diffusion also increases as there is more space for molecules to diffuse across the membrane
Diffusion distance
Diffusion is rapid over very short distances, and slow over longer distances
3 types of passive processes
1) Simple diffusion
2) Facilitated diffusion
3) Osmosis
Simple Diffusion
Nonpolar, hydrophobic molecules (O2, CO2, lipids)
- atoms, or ions move from a higher concentration to a lower concentration without the help of transport proteins
Facilitated diffusion
needs help with transportation due to high polarization
- Integral proteins: membrane channel or carrier and can be used to act as a bridge across plasma membrane
Membrane channel
protein embedded within a cell membrane, allowing specific ions or molecules to passively move across the membrane down their concentration gradient
Carrier
Solute binds to specific transporter, transporter changes shape
- Includes glucose, fructose and galactose
Osmosis
Diffusion of water molecules down their concentration gradient across a selectively permeable membrane
Tonicity
How solution influences the shape of the cell
Hypertonic
Solute concentration higher than another
- RBC: cremation - cell shrinkage, dehydration the concentration of NaCl outside the blood cells is higher than inside, causing water to move out of the cells, leading to cell shrinkage or crenation.
Hypotonic
Water will enter the cell and cell will swell (RBC: hemolysis, inflated)
Isotonic
Two solution with the same concentration
- The cell will maintain normal shape
Primary Active Transport
Transport comes directly from the breakdown of ATP (cell energy)
- Sodium Ion potassium pump: (membrane-embedded protein pump) that uses ATP to move Na+ out of a cell and K+ into the cell
Secondary Active Transport
the energy stored in the form of sodium or hydrogen ion concentration gradient
- a process that moves molecules across a cell membrane using electrochemical energy
Transport in vesicles
1) Endocytosis - materials move into cell in a vesicle formed from the plasma membrane
2) Receptor Mediated endocytosis
3) Phagocytosis- ingestion of solid particles (macrophages and neutrophils)
Endocytosis
Occurs in membrane vesicles
- Cell ingests material by (engulfing) enveloping a portion of its cell membrane and then pinching off that portion of the membrane
Phagocytosis
Ingestion of pathogens, protects body from disease
- Macrophages and neutrophils
Pinocytosis
Ingestion of extracellular fluid and dissolved substances outside a cell vesicles
Receptor-Mediated endocytosis
- the selective uptake of large molecules and particles by the cell.
- Viruses can take advantage to enter cell in plasma membrane vesicles
Exocytosis
ātaking out of the cellā
- cell exports material using vesicular transport
Cytosol
Intracellular fluid made of water, proteins, carbs, lipids, inorganic substances
- Medium for metabolic reactions
- Has a cytoskeleton - made up of protein filaments and provides framework for cell
Centrosomes
- organizes microtubules in interphase of mitosis (cell divison)
- dense areas that contain centrioles.
- Paired cylinders arranges at right angles to each other. (looks like a churro)
Cilia
numerous, short, hairlike projections. Moves material across surface of cell. (help keep lungs clean)
Flagella
longer, moves an entire cell (located on the Sperm Cell)
Riobosomes
tiny spheres; contain our RNA; can be found freely or clustered with endoplasmic reticulum
endoplasmic reticulum
anatomically are flattened sacs/tubules (called cisterns)
Rough ER: continuous with nuclear membrane; outer surface with ribosomes.
Smooth ER: extends from rough ER; has no ribosomes
- Transports substances, stores and packages molecules
- Releases calcium for muscle contractions
Golgi Complex
4-6 stacked membrane sacs (cisterns)
function: process, sort, and deliver proteins, lipids to the plasma membrane, lysosomes, and secretory vesicles
Lysosomes
assist with intracellular digestion of worn out organelles (autophagy) and digestion of cellular contents (autolysis)
- form in the golgi complex; membrane enclosed vesicles; have powerful enzymes.
Perioxomes
similar to lysosomes; but smaller; has enzymes and uses ocygen to breakdown and organize substances
Proteasomes
- Gets rid of unneeded, damaged, faulty proteins.
- The proteases cut the proteins into small peptides
Mitochondria
- power house of the cell; site of ATP production.
- helps with apoptosis (cell death)
- mitochondria is self replicating using their own DNA (inherited from the mother)
Nucleus
- Largest organelle of cell
- Control center, stores genetic instruction for the manufacturing of proteins, contains DNA (genetic code)
- Most cells in body contain one nucleus (muscle cells are multinucleated)
Chromatins
Substance consisting of DNA and associated proteins
- Chromatins twist to become chromosomes
Nucleolus
creates RNA and ribosomes
Nuclear Envelope
Double membrane (2 layered)
Nuclear Pores
- Protein-lined openings
- Tiny passageway for proteins, RNA, and solutes to move b/w the nucleus and cytoplasm
DNA vs RNA
- DNA is double stranded, RNA single stranded
- DNA responsible for storing and transferring genetic information
- RNA directly codes for amino acids and acts as the messenger b/w DNA and ribosomes to make proteins
Mitosis
a phase when the cells divide; division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed
2 major parts of cell cycle
Mitosis and interphase
- Interphase is subdivided into 4 parts
G 0 phase
is for cells that are not actively dividing or never divide, such as some nerve and cardiac muscle cells. Cells that do divide go through phases G1, S, and G2
G 1 Phase
is the first growth phase in the cycle where a cell grows and accumulates the building blocks of DNA, proteins, and energy reserves to carry out DNA replication
S phase
āSā for synthesis), DNA replication occurs and chromosomes are formed
G 2 Phase
The cell duplicates some organelles and synthesizes the proteins
Mitosis Subdivisions
1) Prophase
2) Prometaphase
3) Metaphase
4) Anaphase
5) Telophase
Prophase
First stage of mitosis (and meiosis), characterized by breakdown of the nuclear envelope and condensing of the chromatin to form chromosomes
Prometaphase
The phase of mitosis following prophase and preceding metaphase, characterized by disappearance of nuclear envelope and the appearance of mitotic spindle and kinetochores at the centromeres
Metaphase
Second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell
Anaphase
Third stage of mitosis (and meiosis), chromatids separate into two new nuclear regions of a dividing cell
Telophase
Final stage of mitosis (and meiosis), preceding cytokinesis, characterized by the formation of two new daughter nuclei
Selectively Permeable
Allows certain substances to pass through the membrane
Active vs Passive transport
- Active requires energy to to move substances through cell membrane through concentration gradient
- Passive transport does not require energy and substance move naturally from high concentration to low concentration
