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absence of oxygen
capture energy from their environment
living organisms arize from nonliving
1665 Reidi challenged by showing that larvae can ONLY arise from meat when exposed to air
Theory of inorganic synthesized to form organic
- Under primordial conditions inorganic substances accumilate and synthesize amino acids, which then form larger molecules such as proteins and/or nucleic acids
- Miller 1953
rxs that release energy. These reactions usually need some activation energy - most often heat
rxs that require energy
lowers activation energy for a rx to occur. Do not affect the energy transfer of the reaction and are not consumed by reaction.
allow necessary reactions to take place in ordinary temperatures. Can speed up or slow down a reaction
lock and key model
- substrate = key
- enzyme = lock
- activation site - where lock and key come together.
the enzyme slightly changes to fit the substrate
inorganic (usually iron, zinc, copper).
Molecule that helps enzyme function
- Molecule that helps enzyme funciton
- Organic - vitamins,
Compounds that inhibit enzyme function
- competitive inhibitors
- noncompetitive inhibitors
- allosteric sites
molecules that mimic the substrate and block the enzyme's active site
Molecules that bind at site other than active site, altering the shape of the enzyme's active site and making it unstable
sites other than the active site that are involved in enzyme activity.
Molecules will bind at allosteric sites may stimulate or inhibit the enzyme's activity
principle of enzyme regulation.
Product of the reaction also acts as the inhibitor.
Idea that when low amounds of a compound (amino acid) is present then the enzyme pathway switches "on" and "off" when an abundence is availbe.
Allosteric regulation is an example of what
feedback inhibition. Varying amounts of allosteric compounds can inhibit or stimulate enzyme function therefore regulating enzyme activity.
Describe chemical pathways and give an example
the transfer or energy from on form to another for the use by cells.
An example is metabolism
How are cells and energy related?
Cells create, store, and release energy
require energy - create large molecules from small
release energy - break down large molecules to small
Is anaerobic or aerobic respiration more effecient in producting energy?
Aerobic Respiration - summarize with equation
Glucose + Oxide --> Water + Carbon Dioxide + Energy
Begins with respiration (aerobic or anerobic) by the breakdown of glucose into small amounts of ATP in the cytoplasm of the cell.
10 step process that ultimately converts glucose into a pyruvate (3-carbon compound).
Krebs cycle & electron transport chain (ETC)
During Cellular respiration (aerobic) the breakdown of glucose in and around mitochondrion yielding large amounts of ATP.
Products of glycolysis are further fermented into lactate or ethanol - no additional ATP (like in Krebs and ETC)
Fermentation - give two examples of when this occurs
occurs in simple organisms such as yeast and bacteria
- occurs in oxygen-deficient environments
- such as vertebrate muscle cells after strenuous activity.
2 states of glycolysis
energy investement and energy payoff
energy investment state of glycolysis
2 ATP are expended, and glucose passes through several steps until it is catabolized into two 3-carbon molecules
energy payoff state of glycolysis (include what happens in presense of oxygen -aerobic)
EACH 3-carbon molecule yeilds...
2 pyruvate, 2 ATP and 2 NADH (high energy electron carrier)
In the presense of oxygen -2 pyruvate molecules enter mitochondria and Krebs cycle and ETC
relies on the consumption of other oranisms for food
Opposite of respiration
Photosynthesis and Respiration in relation to glucose and carbon dioxide
Photosynthesis: carbon dioxide reduces to form glucose
Respiration: glucose oxidizes to form carbon dioxide
Reaction mechanism of photosynthesis
water + carbon dioxide + energy --> glucose + oxygen
Where does photosynthesis occur?
chloroplasts of cells
Chloroplasts of photosynthesis is to _____ of cellular respiration
light reactions of photosynthesis occur where?
thylakoid membrane and Calvin-Benson cycle
occurs int he stroma of the chloroplast. Converts the light energy into chemical energy in the form of ATP and NADPH.
Chemical energy is then used to convert carbon dioxide into food.
**requires more ATP than NADPH**
Describe the light reaction that takes palce in the thylakoid membrane
chlorophyll absorbs light (form of photon). Photon is passed till it reaches chlorophyll (a) that is surrounded by a light harvesting complex.
Two types of chlorophyll (a) : P680 produces oxide and hydrogen air while the other (P700) produces ATP.
The energy produced by P700 cycle is used in Calvin-Benson cycle for energy(ATP and NADPH) to cervert carbon dioxide to food.
Kinetic vs Potential energy
- Kinetic energy is the energy of a movig object.
- Potential energy is energy that can be.
Potential energy in biology
Bonds that hold molecules together
1st law of thermodynamics
energy in the universe is neither created or distroyed
Second Law of Thermodynamics
when energy is transferred or transformed, some small amount is lost as unusable energy.
3 Function of membranes
- Separate the cell from its environment
- Devide the cell into different compartments
- Control the passage of substances
Structure of a membrane
lipid bilayer - phospholipids have a hydrophilic polar group (water loving head) on the outside of the membrane and a hydrocarbon chain (water-fearing tail) on the membraine's center.
Membrane proteins are dispersed throughout the lipid bilayer - transport molecules
Why is membrane fluidity important
it can change with temperature, electrical charges, and presence of various electrolytes
Describe selectively permeable
Some molecules can pass through easily (passive transport) and some cannot.
Name two types of passive transport
- Diffusion - particles spreading from areas of high concentration to low.
- Osmosis - movement of water across a semipermeable membrane.
lower concentration of solute
greater concentration of solute
same concentration of solute
cell's process of balancing water concentrations
Maintaining isotonic condiditons. Plants, fungi, and bacteria
No true nucleus and no membrane-bound organelles
Bacteria and archaea
smaller and thought to be more primative
Prokaryotic cells contain:
- cytoplasm bound by a plasma membrane
- genetic material (DNA) - called nucleoid
- Can contain cell wall, pili, flagella, and outer capsule
those that contain a membrane bound nucleus
Difference between eukaryotic cells of plants and animals
- Plants - chloroplasts, central vacuoles, and tonoplasts, cell walls and plasmodesmata
- Animals-lysosomes, centrioles, flagella
Nucleus - functions
- Contain cell's DNA
- Responsible for cellular reproducation
- Responsible for DNA replication
- Responsible for RNA synthesis
- Responses to changes in the cell's environment
- chromatin - condensed material inside
- nucleoli - specialized areas that produce ribosomal RNA and help assemble proteins
- not bound by membranes
- contain small and large subunits
free ribosomes protein
generally remain in the cytoplasm
bound ribosomes protein
generally fuse with membranes of organelles
can ribosomes be found in prokaryotic cells?
Bilayer membrane that secretes enzymes and produces other bilayer membranes
Two types of ER
- Rough- studded with ribosomes and responsible for exporting the proteins
- Smooth- synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs and poisons
What organ has an abundance of smooth ER and why
Liver because of its ability to detoxify of drugs and poisons
How is a protein shipped to another part of the cell?
portion of the ER membrane pinches off creating a transport vesicle containing the protein
- extensive network of flattened membrane-bound besicles.
- closely linked with the ER
Golgi Apparatus contains ________ membrane.
What does the cis and trans faces of a Golgi Apparatus do?
- Cis - receives trasport vesibles from the rough ER
- Trans - buds into a vesicle and transports the protein to its final destination
What is the difference between a bud secretory vesicle or a transport vesicle of the Golgi aparatus?
Secretory vesicles remove the protein completely from the cell by binding with the plasma membrane of the cell and releasing it to space
A transport vesicle transports protein within the cell
What do lysosomes carry?
hydrolytic enzymes that can digest macromolecules into smaller compounds that the cell can use more readily
process of bring substances into the cell
Where does the lysosome and the enyzyme it carries originate? Where is it modified at?
originates in the ER and modified in the golgi apparatus
small sack like, single membrane organelle.
Enzymes of perioxisomes create what?
Hydrogen peroxide, which catabolize large molecules and toxins
Perioxisomes also tranform hydrogen peroxide into?
Large membranous sacs that store food, minerals, waste and other chemical products in plant cells
Vacuoles are similar to?
Both originate from the ER and carry out hydrolysis
Vacuoles as hydrolysis
contract and expel water out of the cell or expand and play a role in cellular elongation
energy powerhouse of the cell
in one cell the number of mitochondria varies from 1 to 1000
Mitochondria is the site of many of the steps of __________.
Krebs cycle occurs within the _______ of the mitochondria
Componenets of the electron transport chain are embedded in the ________ of the mitchondria.
Solar energy in converted into chemical energy by organelles found in plants called ____.
- chlorophyll and other molecules taht absorb the sunlight
- two membranes
- thylakoids - light rx occurs
- stroma - Calvin-Benson cycle occurs here
What is the support stucture of the cell?
- criss-crossing fibers that maintain and change the cell's shape
- microtubules, intermediate filaments, microfilaments
- Hollow rods found mostly in the cytoplasm
- Thickest of all fibers of cytoskeleton
Centrosome or Centrioles
- microtubule organizing center in the cell. Some cells contain two centrosomes (centrioles)
- Play a role in the separation of chromosomes during cell division
composed of cilia and flagella
cilia and flagella functions
locomotion of cells
- protein fibers that maintain the structural intergerty and shape of the cell as well as the arrangement of the organelles within the cell
- more permanent
- twisted double chain of protein called actin
- help the cell change shape
- form the cleavage furrow in cell division
What type of filaments of a cell is responsible for contraction
skin is divided into two sections
- thin outer layer composed of stratified squamous epithelial cells (keratinocytes)
- 5 layers
- no blood vessels or nerves
List the 5 layers of the epidermis
- Corn lovers grow several barrels
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
stratum corneum is composed of...
flattened, dead cells, filled with keratin
What toughens the skin, hair, and nails?
Epidermis contain what two types of cells, other than its 5 layers?
- melanocytes - responsible for brown pigmentation
- Langerhans cells - specialized immune cells
Deris Layer of skin
composed of connective tissue (including collegen and elastic fibers), sparse cells, ang ground substance
What are the cells found in the dermis and which one is the most abundent?
- Fibroblasts - most abundent
- masst cells
The dermis contains what (aside from mast cells, etc)
blood vessels, hair follicles, sweat glands, sebaceous glands, free and specialized nerve endings including Pacinian and Meissner's corpuscles
What is the level below the dermis and what is its function?
Subcutaneous layer - filled with fatty deposits that help store heat as well as blood vessels, nerves and lymphatics