Exam 1 Flashcards
Chemical Level of Organization
Atoms
the smallest units of matter that retain all of the properties of an element
Chemical level:
molecules
consist of two or more atoms that are chemically joined together
Cellular level:
Cells
structural and functional units of life
Cellular level:
organelles
structures, regions, or molecules in a cell that carry out specific tasks
Tissue level:
Tissue
a collection of similar cells that work together to perform a particular function
four types of tissues that make up our bodies
epithelial, connective (bone, cartilage, adipose), muscle, nervous.
Organ level:
organ
consists of two or more tissue types that assume a recognizable shape and perform a particular function
Organ System level:
organ system
a group of organs that perform a unique collective function
Organismal level:
organism
single, completely functional living individual
Homeostasis
The body’s internal environment is maintained within certain physiological limits to establish a dynamic equilibrium for a particular variable.
How is homeostasis maintained
by feedback mechanisms
Negative feedback
occurs when the body detects a change in homeostasis and responds by activating mechanisms that either negate the change or reverse the change.
What is an analogy of negative feedback
a thermostat that controls a furnace
Positive feedback
occurs when the body detects a physiological change and responds by enhancing the original change.
An analogy of positive feedback
accelerating away from a stop signal
anatomical position
feet are placed shoulder width apart, arms at the sides, and palms facing forward
Superior
directs you above or toward the head
inferior
directs you below or toward the tail end.
Anterior
directs you toward the front or belly
posterior
directs you toward the back or spine
Medial
directs you toward the midline of the body
lateral
directs you away from the midline of the body.
Proximal
a point closer to the origin or attachment of a structure
distal
a point farther away from the origin or attachment of a structure.
Superficial
directs you toward the body’s surface
deep
directs you away from the body’s surface.
Supine
the palms facing forward or lying face up
prone
the palms facing rearward or lying face down.
Sagittal plane
passes vertically through the body dividing it into right and left portions.
Frontal plane
a vertical plane perpendicular to any sagittal plane that divides the body into anterior (front) and posterior (back) portions.
Horizontal (transverse) plane
perpendicular to any sagittal or frontal plane and divides the body into superior (upper) and inferior (lower) portions.
Dorsal body cavity
located near the posterior surface.
cranial cavity
formed by the bones of the skull and contains the brain
vertebral canal
formed by the vertebrae and contains spinal cord
dorsal body cavity is lined by
three layers of membranes called meninges
protects the delicate components of nervous system
Dorsal body cavity
Ventral body cavity is located
near the anterior surface and is separated into two regions by the muscular diaphragm.
thoracic cavity is lined by
pleurae and contains the lungs
abdominopelvic cavity is lined by
a membrane called the peritoneum
the most abundant carbon compounds in living organisms
Carbohydrates
provide a major source of energy
Carbohydrates
Monosaccharides
simple sugars that contain three to seven carbon atoms.
isomers
they have the same molecular formula, but different chemical structures
main source of energy for most cells
Glucose
Play in role in building of nucleic acids
ribose and deoxyribose
Disaccharides
form when two monosaccharides are joined by dehydration synthesis.
sucrose
(table sugar) is formed from glucose and fructose and is used to transport sugar in plants
formed from glucose and galactose and is often called “milk sugar“
lactose
formed from glucose and glucose and is a by-product of starch digestion
maltose
Polysaccharides
long chains of glucose molecules that are relatively insoluble in water,which makes them useful storage compounds or structural components.
glycogen
a highly branched polymer of glucose molecules used for energy storage in muscle cells, liver cells, and uterine cells
can be joined to lipids and proteins to form glycolipids and glycoproteins.
Carbohydrates
The only type of biological molecule that isn’t a polymer
Lipids
hydrophobic biological molecules that are insoluble in water
Lipids
store more energy per gram than carbohydrates
lipids
Triglycerides
consist of three fatty acids attached to a glycerol molecule (lipid)
Phospholipids
resemble triglycerides, but a phosphate group replaces one of the fatty acids to make them amphipathic with hydrophobic “tails” and hydrophilic “heads”
complex lipids whose structure contains four rings of carbon atoms.
Steroids
a steroid that comes from animal products and is needed by the body to synthesize sex hormones and other steroids
cholesterol
combines with fat, phospholipids, and proteins to form lipoproteins
Cholesterol
high-density lipoprotein (HDL)
has a relatively low lipid-to-protein ratio
Considered “good” cholesterol that helps prevent cardiovascular disease
low-density lipoprotein (LDL)
has a higher lipid-to-protein ratio
Considered “bad” cholesterol that contributes to cardiovascular disease
the most diverse carbon compounds found in living organisms, comprising between 10 and 30% of cell mass.
Proteins
make up hair, nails, and muscle fibers
structural proteins
carry substances throughout the body
transport proteins
serve as chemical messengers
protein hormones
protect an organism against disease-causing agents
antibodies
catalyze chemical reactions necessary by cells to sustain life
enzymes
A protein’s function is influenced by
its shape based on its levels of structural organization.
usually globular protein molecules that act as biological catalysts to speed up the rate of a biochemical reaction without being changed or used up during the reaction.
Enzymes
lower the activation energy needed to get a chemical reaction started, but they cannot force a chemical reaction to occur
enzymes
An enzyme has a unique shape with a special region called its
active site.
bind to the active site to form an enzyme-substrate complex that will help carry out the reaction
chemical substrates
are often highly specific and may catalyze only a single reaction
enzymes
polymers of nucleotide monomers and are the largest biological molecules in the body.
Nucleic acids
Deoxyribonucleic acid (DNA) consists of
two long chains of deoxynucleotides organized into a double helix.
a nucleotide that contains the sugar ribose, three phosphate groups attached to the 5’ carbon, and adenine attached to the 1’ carbon.
Adenosine triphosphate (ATP)
Cytosol
the intracellular fluid (ICF) in the cytoplasm that surrounds the organelles.
chromatin
a tangled mass of DNA, globular histone proteins, and RNA
primary function of the nucleus
stores genetic information that controls the activities of the cell
Nucleoli
spherical bodies made of protein, DNA, and RNA that assemble ribosomes.
membranous or non-membranous structures or compartments in a cell.
Organelles
cytoskeleton
a system of filaments and tubules that provides internal organization, gives a cell its overall shape, and enables a cell and its organelles to move.
microfilaments
provide mechanical support and participate in muscle contraction, cell division, and cell locomotion
intermediate filaments
provide points of anchorage inside the cell
microtubules
contribute to structure of cilia and flagella and guide movement of chromosomes during cell division
Ribosomes
make proteins that perform specific cellular tasks in the cytosol
rough endoplasmic reticulum (RER
involved in protein synthesis and intracellular transport
smooth endoplasmic reticulum (SER)
involved in lipid synthesis and intracellular transport
Golgi complex
receives newly synthesized proteins from rough endoplasmic reticulum, modifies them, processes them, and then packages them into vesicles for use in the cell or for export out of the cell
Lysosomes
enzymes digest worn-out organelles and recycle them through autophagy
lysosomes may also digest and destroy their own cell through autolysis
Peroxisomes
abundant in liver cells and kidney cells where they can detoxify alcohol and other drugs
Mitochondria
provides the energy
Centrioles
collections of microtubules that play an important role in cell division.
centrosome
two centrioles form an area in the cytoplasm
energy associated with motion
kinetic energy
stored energy
potential energy
stored in chemical bonds that join atoms together
chemical potential energy
First Law of Thermodynamics
energy can NEVER be created nor destroyed, but it can be changed from one form into another form.
Second Law of Thermodynamics
energy transformations MUST lose some useful energy to a useless form that cannot be recovered.
Living systems tend to become more disorganized when
energy is not available.
entropy
measures the randomness or disorder in a system
Glycolysis
“sugar splitting” is the first step in both anaerobic and aerobic respiration.
aerobic respiration
requires that oxygen be available and is much more efficient
anaerobic respiration
occurs when oxygen is not available
Cellular respiration involves four metabolic pathways
glycolysis, formation of acetyl coenzyme A, Krebs cycle, and the electron transport chain.
“prime the pump”
Two molecules of ATP are split and the phosphate groups are added to a molecule of glucose.
where does glycolysis take place
takes place in the cytoplasm of a cell
when does glycolysis take place
when glucose is available
why does glycolysis take place
uses energy stored in the chemical bonds of glucose to form ATP
How does glycolysis take place
- glucose is oxidized to form pyruvic acid
- there is a net gain of two molecules of ATP
- two molecules of NADH are generated to carry high-energy electrons
where does lactic acid formation occur
in overworked muscle cells
when does lactic acid formation occur
when sufficient oxygen is not available.
How does lactic acid formation take place
The pyruvic acid that was formed during glycolysis gets reduced to lactic acid, and NADH gets oxidized back to NAD+ so glycolysis can continue.
where does lactic acid get sent
lactic acid gets sent to the liver where it can be converted back into pyruvic acid
is lactic acid formation efficient?
It is an inefficient pathway because most of the energy in glucose remains in lactic acid, which can be toxic in large quantities.
why does lactic acid formation occur?
to keep glycolysis going
why does the Formation of Acetyl Coenzyme A take place
to get ready for Krebs cycle
when does the Formation of Acetyl Coenzyme A take place
When oxygen is available
How does the Formation of Acetyl Coenzyme A take place
- each pyruvic acid that was produced by glycolysis is transported into a mitochondrion.
- A molecule of carbon dioxide is removed from each molecule of pyruvic acid and NAD+ removes electrons and hydrogen ions to form a pair of two-carbon acetyl groups and two molecules of NADH.
- The acetyl group binds to coenzyme A, forming acetyl coenzyme A, which enters the Krebs cycle.
where does the Krebs cycle take place
in the matrix of a mitochondrion
when does the krebs cycle take place
when oxygen is available
why does the krebs cycle take place
eleases more of the energy that was available in a molecule of glucose
How does the krebs cycle take place
- each of the two molecules of acetyl coenzyme A that enters the Krebs cycle gets oxidized to produce two molecules of carbon dioxide
- two molecules of ATP are produced
- six molecules of NADH are generated to carry high-energy electrons
- two molecules of FADH2 are generated to carry high-energy electron
where does the electron transport chain take place
along the inner membrane of a mitochondrion
when does the electron transport chain take place
when oxygen is available
why does the electron transport chain take place
completes the release of energy that was stored in a glucose molecule
How does the electron transport chain take place
- NADH and FADH2 transfer electrons and hydrogen ions to carriers to make ATP
- oxygen takes low-energy electrons and combines with hydrogen ions to form water
what is The net energy yield from oxidizing one molecule of glucose
36 molecules of ATP.
what percentage of the energy stored in glucose has been converted to ATP.
Approximately 40%
the diffusion of water across a selectively permeable membrane from a region of high water concentration ( low solute concentration) to a region of lower water concentration (High solute concentration)
Osmosis
Osmotic potential
the tendency for one aqueous solution to gain water from another aqueous solution when the two solutions are separated from one another by a selectively permeable membrane.
osmolarity
the number of moles of particles that are dissolved in a liter of solution
the force that blocks the flow of water across a membrane.
Osmotic pressure
the ability of a solution to affect fluid volume and pressure in a cell.
Tonicity
isotonic
two solutions are isotonic if their solute concentrations are on both sides of the membrane
hypertonic
one solution is hypertonic to another solution if its solute concentration is higher than the solute concentration of the solution on the other side of the membrane
crenation
Cells placed into a hypertonic solution will undergo crenation (shrivel)
hypotonic
one solution is hypotonic to another solution if its solute concentration is lower than the solute concentration of the solution on the other side of the membrane
lysis
Cells placed into a hypotonic solution will undergo lysis (bursts)
follows a gradient across a membrane
passive movement
created by difference in chemical concentration on opposite sides of membrane
Concentration gradient
established by difference in distribution of positive and negative charges on opposite sides of membrane
Electrical gradient
describes the movement of particles from a region of high concentration to a region of lower concentration until equilibrium is reached
Diffusion
does not require a membrane ( it can occur with one though)
Diffusion
uses carrier proteins to move molecules across a membrane that might be too large or too polar.
Carrier-mediated transport
uniporters
carry a single substance across a membrane
symporters
carry two or more substances simultaneously across a membrane in the same direction
antiporters
carry two or more substances simultaneously across a membrane in opposite directions (sodium/potassium pump)
describes the transport of molecules along a concentration gradient.
a molecule attaches to a carrier, which changes shape to move the molecule across the membrane
Facilitated diffusion
uses ATP energy to move particles across a membrane against a concentration gradient, from region of low concentration to region of higher concentration.
Active transport
ATP energy changes the shape of a carrier protein causing it to “pump” a substance across a plasma membrane against its concentration gradient.
primary active transport
energy is stored in a concentration gradient and used to “drive” other substances across a membrane against their own concentration gradient.
secondary active transport
transcytosis
transport substances within a cell
endocytosis
bring substances into cell from the extracellular fluid
exocytosis
release substances from cell into the extracellular fluid
phagocytosis
‘cell eating’ is the process of engulfing large particles by special phagocytic cells
pinocytosis
‘cell drinking’ engulfs droplets of extracellular fluid (ecf) that contain dissolved solutes
receptor-mediated endocytosis
enables a cell to take in specific molecules without engulfing very much extracellular fluid
Prokaryotes
simple cells that lack a distinct nucleus.
Eukaryotes
larger, more complex cells with a nucleus and membrane-bound organelles.
glycocalyx
a carbohydrate coating that covers the membrane.
Microvilli
extensions of the membrane that increase the surface area of a cell.
Cilia
short, hair-like projections that protrude from the surface of a cell and they are composed of thin protein microtubules.
Flagella
long, whip-like projections from a cell that move the entire cell (sperm) from one place to another
