Biology Unit 2 Flashcards
Cell Theory
- All organisms have 1+ cells
- Cells come from division of preexisting cells
- Cells pass heredity material to offspring
- Cell is structural and functional unit of all organisms
ALL cells have…
Plasma membrane
Cytoplasm
DNA
Plasma membrane
- Outermost membrane of a cell
- Encloses a jellylike mixture called cytoplasm
- Suspended in the cytoplasm are specialized organelles
All cells start out life with DNA
In eukaryotic cells, DNA is contained within the nucleus
Lipid bilayer
Composition of nearly all cell membranes that’s a double layered sheet
Cell membrane
Regulates what enters and leaves the cells and provides protection and support
Cell
- Every living cell exists in a liquid environment
- Cells=10-20 micrometers in diameter
- Cell size is limited by surface-to-volume ratio
- Volume increases with the cube of the diameter
- Surface area increases with the square
- When cell expands in diameter, it’s volume increases faster then it’s surface area
Soltion
Mixture of two or more substances
Solutes
Dissolved in solution
Solvent
The dissolvent
Concentration
The mass of solute in a given volume of solution, or mass/volume
Diffusion
- Particles in a solution tend to move from an area where they are more concentrated to an area where they are less concentrated
- Spontaneous spreading of molecules or ions
- Essential for substances to move into, through, and out of cells
Equilibrium
The concentration of the solute is the same throughout a system
Fluid mosaic
Model of a cell membrane as a 2-dimensional fluid of mixed composition
Types of proteins
Adhesion, recognition, receptor, & transport
Adhesion proteins
Helps cells stick together
Recognition proteins
Identifies “self” cells
Receptor proteins
Triggers a change in cell activity
Transport proteins
Assists the movement of ions or molecules across the membrane
Nucleus
Protects DNA from the metabolic process of the cell
Nuclear envelope
Outer boundary of the nucleus; controls access to DNA
Nucleoplasm
Viscous fluid enclosed by the nuclear envelope
Nucleuolus
Dense, irregularly shaped region where ribosomal subunits are assembled
Nuclear pore
Pores in our envelope responsible for mRNA
Endomembrane system
- Series of interacting organelles between nucleus and plasma membrane
- Endoplasmic reticulum, Golgi bodies, vesicles
- Produces lipids and proteins
Vesicles
- Small, membrane enclosed organelle
- Transports substances
- Collects and disposes of waste, debris, or toxins
Peroxisome
Breaks down amino acids, fatty acids, and toxic substances
Lysosomes
Breaks down cellular wastes and debris
Vacuoles
Fluid filled; isolates or disposes of waste, debris, or toxic materials
Central Vacuole
Fluid filled vesicle in many plant cells
Endoplasmic Reticulum
A continuous system of sacs and tubes extending from the nuclear envelope
Smooth ER
Makes lipids and breaks down carbohydrates and fatty acids
Rough ER
Ribosomes on the surface synthesize proteins
Golgi body
- Modifies proteins
- Packages the finished products into vesicles
- Some of the vesicles deliver their cargo to the plasma membrane; others become lysosomes
Mitochondria
- Double-membrane organelle that produces ATP by aerobic respiration in eukaryotes
- Nearly all eukaryotic cells have mitochondria (including plant cells)
Plastids
Double-membranes organelles that function in photosynthesis, storage, or pigmentation in plant and algal cells
Chloroplasts
Specialized plastid for photosynthesis in some protists and plant cells
What affects the rate of diffusion?
Size, temperature, concentration, charge, and pressure
Lipid bilayers are selectively permeable
-Water can cross, but ions and polar molecules cannot
Juror pressure/Jurgor?
- Stiff cell walls keep plant cells from expanding very much
- Inflow of water causes pressure to build up
Turgor
Pressure that a fluid exerts against a structure
Osmotic pressure
Amount of Turgor that prevents osmosis into cytoplasm or other hypertonic fluid
Transport proteins
Allow only specific substances to cross the cell membrane
Passive transport
Solutes move through membrane; requires no energy
Active transport
Transport protein pumps a solute against its concentration gradient; requires energy
Active transport: Vesicle movement
Exocytosis, endocytosiss, phagocytosis
Exocytosis
Cell expels a vesicles contents to extracellular fluid
Endocytosis
Cell takes in a small amount of extracellular fluid by the ballooning inward of the plasma membrane
Phagocytosis
“Cell eating” and endocytic pathway by which a cell engulfs particles such as microbes or cellular debris
Membrane proteins and lipids are made:
In the ER and move to the Golgi bodies for final modification
Exocytosis and endocytosis
Continually replace and withdraw membrane patches
In order to use the energy stored in sugars, cells must 1st…
Transfer the sugar to ATP
Energy transfer occurs when…
The bonds of a sugars carbon backbone are broken, driving ATP synthesis
2 main mechanisms break down sugars to make ATP:
Aerobic Respiration and Fermentation
Aerobic Resperation
- Requires oxygen to break down sugars to make ATP
- Releasing pathway in nearly all eukaryotes and some bacteria
- Occurs in the mitochondria of a cell
3 stages of aerobic relegation produce 36 ATP:
Glycolysis, Krebs, ETP
Glycolysis
- Occurs in the cytoplasm; net yield is 2 ATP
- Taking a sugar and breaking it in half
Krebs cycle
Occurs in the mitochondria; net yield is 2 ATP
ETP/Electron transfer phosphorylation
Occurs in the mitochondria; net yield is 32 ATP
Fermentation
- Sugar breakdown pathway that does not require oxygen to make ATP
- Begins with glycolysis in the cytoplasm
- Occurs entirely in the cytoplasm and does not include electron transfer chains
- Net yield is 2 ATP, which provides enough ATP to sustain many single-celled species
Cellular respiration and mitochondria
- Cells require a constant source of energy for life process
- Respiration occurs in ALL cells and can take place either with or without oxygen
Aerobic respiration formula:
C6⃣H1⃣2⃣O6⃣+6O2⃣ to 6CO2⃣+6H2⃣O+36ATP
Glucose+Oxygen to Carbon Dioxide+Water+Energy
Explain Krebs cycle
Explain Krebs cycle
Explain electron transport chain
Explain electron transport chain
Energy
Energy for living things come from food, originally, they come from the sun
Autotrophs
Organism that use LIGHT ENERGY from the sun to produce food
Heterotrophs
Organisms that CANNOT use the Suns every to make food
Cell energy
- Cells usable source of energy called ATP
- All energy is stored in the bonds of compounds, breaking the bond, releases the energy
- When a cell has energy available, it can store this energy by adding a phosphate group to ADP, producing ATP
- ATP is converted into ADP by breaking the bond between the 2nd and 3rd phosphate groups and releasing energy for cellular process
ATP stands for…
Adenosine Triphosphate
Photosynthesis
- The energy of sunlight is converted into the energy of glucose
- Occurs in chloroplasts of plants
Pigment
- Light absorbing compound
- Absorb some wavelengths of light and reflect others(the color our eyes see is the color that the pigment reflects)
Chlorophyll
The pigment inside the chloroplast that absorbs light for photosynthesis
Photosynthesis formula
6CO2⃣+6H2⃣O+light to C6⃣H1⃣2⃣O6⃣+6O2⃣
Carbon dioxide+water+light to glucose+oxygen
Light dependent reaction
H2⃣O is broken down and light energy is stored temporarily in inorganic energy carries, ATP and NADPH
Calvin Cycle
Energy is transferred from ATP and NADPH to the organic compound glucose
Osmosis
Diffusion of water across a permeable membrane
Hypotonic
A fluid that has a low solute concentration
Hypertonic
A fluid that has a high concentration
Isotonic
2 fluids with identical solute concentrations
