Bio 101 Final Exam

Chapters 6, 7, 10, 12, 18 (Only Typtophan Operon)

Unicellular

Single celled, bacteria and archaea

Multicellular

Many cells, plants, fungi, and animals

Light microscope

Microscope where visible light passes through a specimen then through a glass lens

Magnification

Ratio of an object's image size to the real size

Resolution

Measure of clarity of an image; not blurry, can see solid lines and distinguish the distance between two points

Contrast

Visible difference in parts of the sample, often using dyes or coloring agents

Electron microscope

Microscope where high intensity electron beam is used, can identify organelles

Plasma membrane, DNA, cytoplasm, ribosomes

4 basic features common to all cells

Prokaryotic

Cells before nucleus was created, no membrane-bound organelles

Nucleoid

Unbound region which holds DNA in prokaryotic cells

Eukaryotic

Cells with a nucleus and membrane-bound organelles

Nucleus

Contains most of the DNA within the cell

Nuclear envelope

Encloses the nucleus, separating it from the cytoplasm; contains a double membrane

Chromatin

Genetic material formed from DNA and proteins

Chromosomes

Condensed chromatin

Ribosomes

Made of rRNA and protein

Ribosomes

Carry out protein synthesis

Free ribosomes

Ribosomes in the cytosol of a cell

Bound ribosomes

Ribosomes attached to the ER or nuclear envelope

Mitochondria

Powerhouse of the cell, synthesizes ATP

Cristae

The inner folds of the mitochondria which synthesize ATP

Respiration

Metabolic process that generates ATP

Phosphate bonds

Where energy is stored in ATP

Rough ER

Covered in ribosomes, makes proteins

Smooth ER

No ribosomes; makes lipids, detoxes poison, metabolizes carbs, stores calcium

Smooth

ER that makes lipids

Golgi apparatus

Where processing and packaging of molecules takes place

Golgi Apparatus

Modifies products of ER, sorts and packages materials into transport vesicles

Vacuoles

Primarily in plant cells; used for storage, may also store pigments and toxins

Plasma membrane

Selectively permeable phospholipid bilayer which allows oxygen and nutrients into cell and waste out of the cell

Chloroplast

Site of photosynthesis and contains green pigment called chlorophyll and other molecules which function in photosynthesis

Thylakoids

Exact site of photosynthesis, shaped like a poker chip

Granum

Stack of thylakoids

Stroma

Empty fluid portion inside the chloroplast

Stroma : chloroplast

Cytosol : cell, but for plants

Cytoskeleton

Network of fibers found in cytoplasm, skeleton of the cell

Microtubules

Thickest of the 3 main types of fibers in the cytoskeleton

Microfilaments

Thinnest of the 3 main types of fibers in the cytoskeleton

Intermediate filaments

Mid-sized filament of the 3 types of fibers in the cytoskeleton

Cytoskeleton

Supports and maintains cell shape, anchors organelles

Cell wall

Protects plant cell, maintains shape, and prevents bursting by massive uptake of water

Structure of cell wall

Made of cellulose fibers embedded in other polysaccharides and protein

Extracellular matrix

Make up for lack of cell wall in animal cells; supports cell structure, promotes cell-to-cell adhesion, and movement of substances across cell

Intercellular junctions

The connections between one cell and the other

Tight junctions

Prevent leakage of extracellular fluid

Stomach

Example of tight junctions

Desmosomes

Junction with interlocking joints to resist tear and strain

Skin

Example of desmosomes

Gap junctions

Communication channels in animal cells

Plasmodesmata

Communication channels in animal cells

Animal cells

Gap junctions provide communication for this type of cell

Plant cells

Plasmodesmata provide communication for this type of cell

Cell wall, ECM

Extracellular structures which provide protection

ECM, junctions

Extracellular structures which provide communication between cells

ECM, junctions

Extracellular structures which provide transport of substances in and out of the cell

Lipids and proteins

Composition of the plasma membrane

Phospholipids, cholesterol, glycolipids

3 types of lipids in plasma membrane

Percentage of phospholipids in plasma membrane (out of all lipids)

75%

Percentage of cholesterol in plasma membrane (out of all lipids)

20%

Percentage of glycolipids in plasma membrane (out of all lipids)

5%

Integral proteins

Proteins which are completely integrated into the plasma membrane

Peripheral proteins

Proteins only found on one side of membrane; do not penetrate fully

Fluid mosaic model

Structural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer

Lack of rigidity

Property of plasma membrane which allows for processes such as phagocytosis and cell signaling

Phagocytosis

Cell eating

Cell signaling

The process of quick cell-to-cell communication mediated by signaling molecules and membrane receptors

Amphipathic

Phospholipids are this type of molecule; made of both hydrophobic and hydrophilic structures

Cholesterol

Offers stability to the cell membrane

Glycolipids

Formed when carbohydrates covalently bind to lipids in plasma membrane

Hydrophobic

Molecules that dissolve into the bilayer and pass freely

Hydrocarbons and fatty acids

Examples of hydrophobic molecules

Hydrophilic

Molecules that cannot cross the plasma membrane on their own and need the help of an integral transport protein

Water and sugars

Examples of hydrophilic molecules

Nonpolar

Property of hydrophobic molecules

Polar, ionic

Property of hydrophilic molecules

Brownian motion

Chaotic movement of particles causing them to travel to the place of least resistance; concentration gradient

Integral proteins

Have both hydrophobic and hydrophilic regions, only move hydrophilic molecules

Integral proteins

Function as transport proteins, enzymes, or receptors

Peripheral proteins

Loosely attached to integral proteins and can be found on either side of the membrane

Peripheral proteins

Function as enzymes but also play a role in cell-to-cell connections; do not transport anything

Transport

Function of membrane proteins where integral provides hydrophilic channel across membrane; also hydrolyze ATP

Enzymatic activity

Function of membrane proteins where they catalyze sequential steps of a metabolic pathway

Enzyme : substrate

Similar to receptor : ligand

Signal transduction

A membrane protein may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. The external messenger (signal) may cause a conformational change in the protein (receptor) that relays the message to the inside of the cell.

Ligand binds to receptor

First step of signal transduction

Pathway sends signal to the cell

Second step of signal transduction

Initiation of chemical reactions

Third step of signal transduction

Hormone or pathogen

Ligand possibilities

Cell-cell recognition

Membrane protein function where they may identify glycoproteins that serve as ID tags

Antibody or antigen

Glycoprotein possibilities in cell-cell recognition

Intercellular joining

Membrane protein function where they may hook together with adjacent cells to provide temporary binding sites that guide cell migration and other cell-to-cell interactions

Attachment to cytoskeleton and ECM

Membrane proteins connect to microfilaments/ cytoskeletal components to maintain cell shape, stabilize membrane protein location

Diffusion

Movement of substances from high to low concentration

Facilitated diffusion

Diffusion aided with the help of a transport protein

Concentration gradient

The difference in concentration of a substance from one area to another

Osmosis

Diffusion of water molecules across a selectively permeable membrane

Low

High solute concentration → ______ water concentration

High

Low solute concentration → ______ water concentration

Tonicity

The ability of a solution to cause a cell to gain or lose water

Tonicity

The measure of solute concentration in a solution