Cell theory
all organisms are composed of cells
What are the basic living unit of structure and function in organisms?
cells
Nucleus
stores DNA, controls cell's activities, bound by nuclear envelope
Nucleoid
prokaryotic, stores DNA (coiled), not membrane bound
Nucleolus
inside the nucleus, site of rRNA synthesis
Ribosomes
protein synthesis, found on the rough ER or floating in cytoplasm
Vesicles
movement and transport, storage and export for distribution
Smooth ER
synthesizes lipids, oils and steroids, deoxification of drugs, filter of the cells
Rough ER
folds and process proteins, packages proteins in vesicles and sends to Golgi apparatus, rough due to ribosomes
Golgi apparatus
mailroom of the cell, modifies products of rough ER
Lysosomes
garbage disposal of the cell, breaks down worn out cell parts
Chloroplasts
site of photosynthesis
Mitochondria
powerhouse of the cell, cellular respiration takes place here
What do small cells require less of?
nutrients
What do small cells produce less of?
wastes
What do larger cell surface areas facilitate?
efficient exchange of nutrients and wastes
Endosymbiotic theory
eukaryotic cells evolved from prokaryotic cells
Fluid-Mosaic model
hydrophilic head, hydrophobic tails, selectively permeable
Fluid
phospholipid bilayer
Mosaic
proteins are embedded
Channel proteins
passageway for certain molecule to get through
Example of channel proteins
aquaporins help water to get across the membrane
Carrier protein
combines with substances to help them cross the membrane
Example of carrier proteins
GLUT carriers transfer glucose into and out of cell
Cell recognition protein
glycoproteins which help the body recognize which cells belong to it (helps with immunity)
Receptor proteins
distinct shape for binding with specific molecules
Enzymatic proteins
carry out metabolic reactions
Hypertonic
water leaves cell, higher concentration of solute outside, shrivels
Hypotonic
water enter cells, higher concentration of solute inside, bursts
Isotonic
no movement of water
What is diabetes?
high concentration of blood glucose
Kinetic energy
energy of motion
Potential energy
stored energy
Chemical energy
food
Mechanical energy
Walking (a type of kinetic energy)
Fist Law of Thermodynamics
energy cannot be created or destroyed, but it can be changed from one form to another
Second Law of Thermodynamics
energy cannot be changed from one dorm to another without a loss of usable energy
Entropy
the relative amount of disorganization in a system
Free energy
amount of energy available after a chemical reaction
Metabolism
all the chemical reactions that take place in a cell
Anabolism
building up molecules
Catabolism
breaking down molecules
Metabolic pathway
one enzyme per step
Endergonic reactions
require input of energy to occur (muscle contraction)
Exergonic reactions
spontaneous (products have less free energy than reactants) and releases energy (respiration)
Functions of ATP
chemical work, transport work, mechanical work
Chemical work
supplies energy for making macromolecules
Transport work
supplies energy to pump substance across plasma mebrane
Mechanical work
supplies energy for muscle contraction, movement of chromosomes
Coupled reactions
reactions that must be paired with each other to be energetically favorable and proceed
Energy of activation
energy that must be added to start chemical reactions, lowered by enzymes
What factors affect enzyme speed?
temperature and pH
Enzyme inhibition
substrate cannot bind to active site
Competitive inhibition
product binds to active site
Non-competitive inhibition
produce binds to other part of enzyme and changes active site shape
Feedback inhibition
regulate enzyme activities by allowing excess products to bind to the active site and inhibits substrate from binding
Oxidation-reduction reaction
reactions that involve the gain and loss of electrons
OIL RIG
oxidation = lose electrons
reduction = gain electrons
What does the active site of enzymes combine with?
substrates
Enzyme shape changes to form what?
enzyme-substrate complex
Coupled reaction example
ATP breakdown/ phosphorylation
More organized entropy
more potential energy, less stable
Less organized entropy
less potential energy, more stable
Cellular respiration equation
O2 + C6H12O6 -> CO2 + H2O + ATP
How many total ATP are produced in cellular respiration?
38
Steps of cellular respiration
glycolysis, citric acid cycle, electron transport chain
Glycolysis
cytoplasm
glucose (6 carbon) -> pyruvate (2-3 carbon molecules)
Glycolysis input
glucose, 2 NAD, 2 ATP, 4 ADP+P
Glycolysis output
2-3 carbon pyruvate, 2 NADH, 2 ADP, 4 ATP
Glycolysis net output
2 ATP
Citric acid cycle
matrix, happens 2 times
Citric acid cycle input
2 acetyl CoA, 6 NAD+, 2 FAD, 2 ADP+P
Citric acid cycle output
4 CO2, 6 NADH+, 2 FADH2, 2 ATP
Citric acid cycle net output
2 ATP
Electron transport chain
cristae
Electron transport chain inputs
NADH, FADH2, O2
Electron transport chain output
ADP, H2O
Electron transport chain net output
32-34 ATP
Photosynthesis equation
CO2 + H2O -> C6H12O6 + O2 + H2O
Steps of photosynthesis
light reactions and calvin cycle
Step 1 of light reactions
solar energy absorbed in choloropyll
Step 2 of light reactions
drives transfer of electrons and H+
Step 3 of light reactions
water is split to replenish lost electrons
Step 4 of light reactions
solar energy reduces NAD+ to NADPH by adding 2 electrons plus hydrogen
Step 5 of light reactions
produces ATP by adding phosphate group to ADP (phosphorylation)
Light reactions inputs
light energy, H2O, NADP+, ADP
Light reactions outputs
O2, ATP, NADPH
Step 1 of Calvin cycle
carbon goes to carbohydrates by adding electrons from NADPH
Step 2 of Calvin cycle
requires 2 ATP to power reaction
Step 3 of Calvin Cycle
reaction is carbon fixation, glucose is the product
Calvin cycle inputs
CO2, ATP, NADPH
Calvin cycle outputs
glucose, ADP, NADP+
The cell theory states:
a) cells form as organelles and molecules become grouped together in an organized manner
b) the normal functioning of an organism does not depend on its individual cells
c) the cell is the basic unit of life
d) only eukaryotic orga
c
As the size of a cell decreases, the ratio of its surface area to volume:
a) increases
b) decreases
c) stays the same
a
Which of the following would not be found in a prokaryotic cell?
a) organelles
b) DNA
c) nucleoid
d) nucleus
d
The ______ is involved in the movement of a prokayrotic cell.
a) fimbriae
b) capsule
c) nucleoid
d) flagella
d
Small circular pieces of DNA that are found in the cytoplasm of a prokaryotic cell are called:
a) capsules
b) nucleoids
c) plasmids
d) ribosomes
c
Eukaryotic cells contain
a) a nucleus
b) DNA
c) plasma membrane
d) mitochondria
e) all of the above
e
The combination of DNA and protein in the nucleus of a eukaryotic cell is called:
a) nuceloplasm
b) plasmids
c) nucleoids
d) chromatin
d
This organelle acts as a digestive organelle and may also be used to recycle the internal components of a cell.
a) ribosome
b) lysosome
c) peroixsome
d) Golgi apparatus
c
The mitochondria of a eukaryotic cell is the site of
a) photosynthesis
b) fatty acid metabolism
c) cellular respiration
d) protein synthesis
c
This component of the cytoskeleton is located just under the plasma membrane of a eukaryotic cell.
a) actin filaments
b) microtubules
c) centrosomes
d) intermediate filaments
a
Centrosomes and centrioles act as organized centers for what component of the cytoskeleton?
a) actin filaments
b) microtubules
c) intermediate filaments
d) all of these are correct
b
The endosymbiotic theory explains the origins of which of the following components of a eukaryotic cell?
a) mitochondria
b) chloroplasts
c) internal membranes
d) all of these are correct
d
According to the endosymbiotic theory, the ______ were originally photosynthetic bacteria.
a) ribosomes
b) chloroplasts
c) mitochondria
d) nucleus
b
In the fluid-mosaic model, the fluid properties are associated with the nature of the _____ and the mosaic pattern is established by the ______.
a) nucleic acids phospholipids
b) phosphsolipids; embedded proteins
c) embedded proteins; cholesterol
d) phosp
b
Which of the following is not a function of proteins in the plasma membrane?
a) proteins assists the passage of materials into the cells
b) proteins interact with and recognize other cells
c) proteins bind with specific hormones
d) proteins carry out spec
e
The carbohydrate chains projecting from the plasma membrane are involved in
a) adhesion between cells
b) reception of molecule
c) cell-to-cell recognition
d) all of these are correct
d
When a cell is placed in a hypotonic solution,
a) solute exits the cell to equalize the concentration on both sides of the membrane
b) water exits the cell toward the area of lower solute concentration
c) water enters the cell toward the area of higher so
c
When a cell is placed in a hypertonic solution,
a) solute exits the cell to equalize the concentration on both sides of the membrane
b) water exits the cell toward the area of lower solute concentration
c) water enters the cell toward the area of higher s
c
Which of the following is incorrect regarding facilitated diffusion?
a) it is a passive process
b) it allows the movement of molecules from areas of low concentration to areas of high concentration
c) it may use either channel or carrier proteins
d) it al
b
The sodium-potassium pump
a) helps establish an electochemical gradient across the membrane
b) concentrates sodium on the outside of the membrane
c) uses a carrier protein and chemical energy
d) is present in the plasma membrane
e) all of these are correc
e
Which of the following processes is involved in the bulk transport of molecules out of the cell?
a) phagocytosis
b) pinocytosis
c) receptor-mediated endocytosis
d) exocytosis
e) none of these are correct
d
Which process uses special proteins on the surface of the membrane to identify specific molecules for transport into the cell?
a) phagocytosis
b) pinocytosis
c) receptor-mediated endocytosis
d) exocytosis
c
The extracellular matrix
a) assists in the movement of substances across the plasma membrane
b) prevent the loss of water when cells are placed in a hypertonic solution
c) has numerous functions that affect the shape and activities of the cell that produc
c
Which of the following junctions allows for cytoplasm-to-cytoplasm communication between cells?
a) adhesion junctions
b) tight junctions
c) gap junctions
d) none of these are correct
c
The fact that energy transformations increase the amount of entropy is the basis of which of the following?
a) cell theory
b) first law of thermodynamics
c) second law of thermodynamics
d) oxidation-reduction reactions
c
Th energy stored in the carbon-carbon bonds of glucose in an example of ______ energy.
a) kinetic
b) potential
c) chemical
d) mechanical
e) both b and c are correct
e
During energy transformations, the majority of energy is converted to,
a) chemical bonds
b) heat
c) ATP
d) glucose molecules
b
Exergonic reactions
a) are spontaneous
b) have a negative G value
c) release energy
d) all of these are correct
d
Which of the following is incorrect regarding ATP?
a) it is the energy currency of the cell
b) it is stable
c) it is recycled using ADP and inorganic phosphate
d) cells keep only small amounts of ATP on hand
b
The sum of all the chemical reactions in a cell is called
a) free energy
b) entropy
c) metabolism
d) oxidation-reduction reactions
c
Which of the following is incorrect regarding the active site of an enzyme?
a) is unique to that enzyme
b) is the part of the enzyme where its substrate can fit
c) can be used over and over again
d) is not affected by environmental factors, such as pH and
d
Which of the following environmental conditions may have an influence on enzyme activity?
a) substrate concentration
b) temperature
c) pH
d) all of these are correct
d
In which of the following does an inhibit bind to a site other than the active site of the enzyme?
a) competitive inhibition
b) noncompetitive inhibition
c) redox reactions
d) none of these are correct
b
Enzymes catalyze chemical reactions by which of the following?
a) lowering the energy of activation in the reaction
b) raising the energy of activation in the reaction
c) increasing entropy
d) increasing the free energy of the products
a
The gain of electrons by a molecule is called
a) inhibition
b) entropy
c) oxidation
d) reduction
d
In which of the following processes is carbon dioxide reduced to form carbohydrate?
a) cellular respiration
b) noncompetitive inhibition
c) photosynthesis
d) induced fit model
c
During glycolysis, what is the net production of ATP per glucose molecule?
a) 0
b) 1
c) 2
d) 8
e) 32-34
c
Which of the following is not a product or reactant of glycolysis?
a) NADH
b) ATP
c) pyruvate
d) oxygen
d
Which of these is incorrect regarding fermentation?
a) there is a net gain of only 2 ATP per glucose
b) it occurs in the cytoplasm
c) the process starts with glucose entering glycolysis
d) NADH donates electrons to the electron transport chain
e) it is an
d
Fermentation is primarily involved in the recycling of
a) ADP
b) oxygen
c) pyruvate
d) NAD+
d
The greatest contributor of electrons to the electron transport chain is
a) oxygen
b) the prep reaction
c) glycolysis
d) fermentation
e) the citric acid cycle
e
Which of these is not true of the citric acid cycle?
a) the citric acid cycle includes the prep reaction
b) the citric acid cycle produces ATP by substrate-level ATP synthesis
c) the citric acid cycle occurs in the mitochondria
d) the citric acid cycle pr
a
Which of these is not true of the electron transport chain?
a) located on the cristae of the mitochondria
b) produces more NADH than any metabolic pathway
c) contains cytochrome molecules
d) ends when oxygen accepts electrons
b
The oxygen required by cellular respiration is reduced and becomes part of which molecule?
a) ATP
b) pyruvate
c) H2O
d) CO2
c
The function of light reactions is to
a) obtain CO2
b) make carbphydrate
c) convert light energy into usable form of chemical energy
d) regenerate RuBP
c
The Calvin cycle reactions
a) produce carbohydrate
b) convert once form of chemical energy into a different form of chemical energy
c) regenerate more RuBP
d) use the products of the light reactions
e) all of these are correct
e
The final acceptor of electrons during the light reactions of the noncyclic electron pathway is
a) PS I
b) PS II
c) ATP
d) NADP+
e) water
d
The oxygen given off by photosynthesis comes from
a) H2O
b) CO2
c) glucose
d) RuBP
a
The noncyclic electron pathway, but not the cyclic pathway, generates
a) 3PG
b) chlorophyll
c) ATP
d) NADPH
d
The ATP and NADPH from the light reactions are used to
a) split water
b) cause RuBP carboxylase to fix CO2
c) re-form the photosystems
d) cause electrons to move along their pathways
e) convert 3PG to G3P
e
In the absence of sunlight, plants are not able to engage in the Calvin cycle due to a lack of
a) ATP
b) oxygen
c) NADPH
d) both a and c are correct
d
Cellular respiration and photosynthesis both
a) use oxygen
b) produce carbon dioxide
c) contain an electron transport chain
d) occur in the chloroplast
c
Which o the following does not occur in photosynthesis?
a) reduction of CO2
b) oxidation of water
c) reduction of oxygen
d) all of these are correct
c