ap bio chapter 2 test

Surface area to volume ratio essential knowledge

Affect the ability of a biological system to obtain necessary nutrients, eliminate waste products, acquire or dissipate thermal energy, and other wise exchange chemicals and energy with the environment.

The surface area to volume ratio can restrict size and shape.

Smaller cells typically have a higher surface area to volume ratio as well as a more efficient exchange of materials with the environment than do larger cells.

When a cells volume increases

The surface area to volume ratio decreases and the demand for internal resources increases

Necessary to adequately exchange material with the environment

More complex cellular structures

As organisms increase in size the sa to volume what?

Decreases affecting properties like rate of heat exchange with the environment. Smaller amounts of mass exchange proportionally more heat with the ambient environment than do larger masses. As mass increases both the surface area to volume ratio and the rate of heat exchange decreases.

The relationship between metabolic rate and body mass

The smaller organism will have the higher metabolic rate per unit body mass.

Phospholipids

Have both hydrophilic and hydrophobic regions. Polar hydrophilic regions are external or internal environment. Non polar hydrophobic regions face the interior.

Embedded proteins

Hydrophilic, hydrophobic, or both

Hydrophilic is inside the interior of the protein or exposed to cytosol

Hydrophobic regions of proteins make up the protein surface that interacts with the fatty acids in the interior membrane

Plasma membranes

Consists of phospholipid molecules embedded with proteins, steroid (such as cholesterol in vertebrate animals), glycoproteins, and glycolipids.

What do plasma membrane do

Separate the internal environment of the cell from the external environment.

Selective permeability

The result of the plasma membrane having a hydrophobic interior.

How do nonpolar small molecules move across membrane

Freely pass the membrane

Cells moving across membrane Hydrophilic substances large polar molecules and ions

Through embedded channels and transport proteins

Pass through in small amounts

Small uncharged molecules like H O 2 or NH3 pass through in small

The selective permeability of membranes causes what

Allows for the formation of concentration gradients of solutes across the membrane

Passive transport

Is the movement of molecules from regions of high concentration gradients to regions of low concentration without the direct input of metabolic energy

Active transport

Requires the direct input of energy to move molecules. Sometimes moves molecules from regions of low to regions of high.

Endocytosis

The cell takes in large molecules and particulate matter by folding the plasma membrane in in itself and forming new small vestibules that engulf material from the external environment

Exocytosis

Internal vestibules release material from cells by fusing with the plasma membrane and secreting large molecules from the cell

Facilitated diffusion

Requires transport or channel protein to enable the movement of charged ions across the membrane

*membranes may become polarized by the movement of ions across the membrane

*charged ions require channel proteins to move through membrane

Facilitated diffusion movement

Enables the large polar molecules through membranes with no energy input. Substance move down the concentration gradient

Aquaporins

Transport large quantities of water across membrane

Ribosomes

made up of ribosomal RNA and protein

Non membrane sub cellular structures are found in cells in all forms of life and reflect the common ancestry

Synthesize proteins according to messenger RNA sequences

endomembrane system

Consists of a group of membrane-bound organelles and sub cellular components that work together to modify, package, and transport polysaccharides, lipids, and proteins intercellularly.

Endoplasmic reticulum

Provides mechanical support by helping cells maintain shape and plays a role in intracellular transport

rough ER

Is associated with membrane bound ribosomes, allows for the compartmentalization of cells, and helps carry out protein synthesis

Smooth er

Functions include the detoxification of cells and lipid synthesis

Golgi complex

Is a membrane bound structure that consists of a series of flattened membrane sacs

Functions are correctly folding and chemically modifying newly synthesized cellular products, packaging proteins for trafficking.

Mitochondria

Have a double membrane that provides compartments for different metabolic reactions involved in aerobic cellular respiration.

The outer membrane is smooth while the inner is highly convoluted.

Mitochondria functions

Forming folds that enable ATP to be synthesized more efficiently

Lysosomes

Are membrane enclosed sacs that contain hydrolytic enzymes that digest material also play a role in programmed cell death (apoptosis)

Vacuoles

Are membrane bound sacs that play many different roles

Vacuoles in plant cells

A specialized large (one of these) maintains turgor pressure through nutrient and water storage

Vacuoles in animal cells

Smaller in size are more plentiful than in plant cells, and store cellular materials.

Chloroplasts

Specialized organelles that are found in plants and photosynthetic algae. Contains a double membrane and serve as the location for photosynthesis.

Movement of water

Hypotonic to hypertonic regions

Osmosis

Water moves from regions of high water potential to regions of low water potential

Growth and homeostasis

Are maintained by the constant movement of molecules across membranes

Osmoregulation

Maintains water balance and allows organisms to control their internal solute composition and water potential.

Osmolarity

Another phrase foe solute concentration

Low osmolarity to regions of high osmolarity

The movement of water

Metabolic energy is required for what

Active transport of molecules and ions across the membrane and to establish and maintain electrochemical gradients

Membrane protein

Are necessary for active transport.

Na/K pump and ATP

Contribute to the maintenance of the membrane potential by the pump using ATP to move positive and negative ions against the concentration gradients

Membrane potential

Difference in electronegative charge between the inside and outside of a cell

Membranes and membrane bound organelles in eukaryotic cells

Compartmentalize intra cellular metabolic processes and specific enzymatic reactions

Compartmentalization

The organization of cellular activities into distinct membrane bound regions to isolate incompatible processes and increase efficiency.

Intracellular metabolic processes

The sum of all chemical reactions occurring with a cell including energy production, molecule synthesis, and waste breakdown

Specific enzymatic reactions

Highly selective chemical processes where an enzyme lowers the energy barrier to create the product (catalyst) to transform a specific molecule called a substrate into a product.

Endosymbiosis

Membrane organelles such as mitochondria and chloroplasts evolved from once free living prokaryotic cells using this process

Prokaryotes compartmentalization

Typically lack internal membrane bound organelles but have internal regions with specialized structures and functions

Eukaryotic compartmentalization

Maintain internal membranes that partition the cell into specialized regions.

Prokaryote cells (bacteria)

Have no defined nucleus

Divided by binary fission

Contains very little specialization within the cell

Unicellular

DNA single loops

Eukaryote cell (plants and animals)

Multicellular

Distinct nucleus

Replicate by mitosis and meiosis

Have specialized membrane enclosed organelles

More organelles then the other type of cell

Nucleoid

A region within bacteria where most of the DNA is found with some RNA and proteins not bounded by a membrane

Genophore

Bacterial chromosome contained in nucleoid region

Plasmid

Can be transferred between bacteria

Ribosomes

Gives the cytoplasm a granular appearance smaller than eukaryotic cells are the site for messenger RNA translation into proteins

Cytoplasm

Internal soup of the cell that is bounded on the outside by the cell envelope.

Capsule

Made of polysaccharides and sometimes protein protects cell by acting as a barrier against phagocytosis by white blood cells

Cell envelope

The cytoplasm is bounded on the outside by this it divides membrane into two groups

Pili, Fimbriae

Hollow hairlike structures made up of proteins how bacteria attaches to other cells. Can transfer DNA between bacterial cells.

Flagella

Long appendages containing micro tubules used for motility they rotate by means of a motor located just under the cytoplasmic membrane