prelims Flashcards
- Study of cells
Cytology
- Study of tissues
• Histology
- Study of structures & parts
• Anatomy
-Study of functions of organisms & their parts
• Physiology
- study of the different forms of organisms
• Morphology
- Study of heredity
• Genetics
- Study of the interaction of organisms with their
environment
• Ecology
- Study of the diversity of organisms (classification
based on their evolutionary relationships– Taxonomy)
• Systematics
– study of insects
• Entomology
- study of amphibians and reptiles
• Herpetology
- study of fishes
• Icthyology
- study of mammals
• Mammalogy
- study of birds
• Ornithology
- study of protozoa
• Protozoology
Two approaches are used to understand natural causes for
natural phenomena
• Discovery science —uses verifiable observations and
measurements to describe science
• Hypothesis-based science —uses the data from discovery
science to explain science
– This requires proposing and testing of hypotheses
—uses verifiable observations and
measurements to describe science
• Discovery science
—uses the data from discovery
science to explain science
– This requires proposing and testing of –
• Hypothesis-based science
is a proposed explanation for a set of
observations
A hypothesis
is supported by a large and usually growing body
of evidence
• A theory
is the genetic (hereditary) material of all cells
– A gene is a discrete unit of –
– The chemical structure of – accounts for its function
– The diversity of life results from differences in – structure
from individual to individual
DNA
is a discrete unit of DNA
A gene
- the complex organization of living things (Cells
as the basic unit of life)
• Order
—an ability to maintain an internal
environment consistent with life
• Regulation
—consistent growth and
development controlled by DNA
• Growth and development
—acquiring energy and
transforming it to a form useful for the organism
• Energy processing/Metabolism
—an ability to respond to
environmental stimuli
• Responsiveness/ Irritability
—the ability to perpetuate the species
• Reproduction
—acquisition of traits that best suit the
organism to its environment (evolutionary adaptation)
• Adaptability
animals (depend on other
organisms for food)
Heterotrophs
plants (can make their own food)
Autotrophs
animals (Can move on their own)
Motile
(cannot move on their own)
Stationary
Carbon (C) element as the
backbone (except CO2)
C usually accompanied with
Hydrogen (H)
Associated with living
organisms
Ex. Sugars, DNA, fats,
proteins
ORGANIC
Do not contain C (except
CO2)
Not associated with living
organisms
Ex. water, gases, salts, metals,
INORGANIC
Carbohydrates
Lipids
Proteins
Nucleic Acids
ORGANIC COMPOUNDS
(Biomolecules/Macromolecules)
are found throughout the cell both as parts of cell structures and as enzymes. The
flagellum is a structure involved in swimming motility.
Proteins (brown)
DNA (green) is found in the nucleoid of prokaryotic cells and in the nucleus of eukaryotic
cells. RNA (orange) is found in the cytoplasm (mRNA, tRNA) and in ribosomes (rRNA).
(b) Nucleic acids.
are located in the cell wall and occasionally in internal storage granules.
(c) Polysaccharides (yellow)
are found in the cytoplasmic membrane, the cell wall, and in storage granules.
(d) Lipids (blue)
=C,H,O
Carbohydrates
- Monosaccharides –1 sugar (building block of CHO)
- Disaccharides –2 sugars
- Polysaccharides –many sugars
Types of Carbohydrates:
–1 sugar (building block of CHO)
- Monosaccharides
–blood sugar
eg. glucose
–fruit sugar
fructose
–a sugar found in milk
galactose
–2 sugars
- Disaccharides
- table sugar ( 1 glucose + 1 fructose)
eg. Sucrose
–malt sugar ( 2 glucose)
maltose
–milk sugar ( 1 glucose + 1 galactose)
lactose
–many sugars
- Polysaccharides
–storage form of sugars in plants
eg. Starch
- storage form of sugars in animals; in liver & muscles
Glycogen
- in cell wall of plants
Cellulose
–in exoskeletons of insects & crustaceans; in cell wall of fungi
Chitin
eg. glucose –blood sugar
fructose –fruit sugar
galactose –a sugar found in milk
- Monosaccharides –1 sugar (building block of CHO)
eg. Sucrose- table sugar ( 1 glucose + 1 fructose)
maltose –malt sugar ( 2 glucose)
lactose –milk sugar ( 1 glucose + 1 galactose)
- Disaccharides –2 sugars
eg. Starch –storage form of sugars in plants
Glycogen - storage form of sugars in animals; in liver & muscles
Cellulose- in cell wall of plants
Chitin –in exoskeletons of insects & crustaceans; in cell wall of fungi
- Polysaccharides –many sugars
Source of energy (E)
Stores E
Structural functions
Functions of Carbohydrates
= (C, H, less O)
Lipids
= heterogenous: no common bldg. block but all are common in terms of physical characteristics:
eg. Not soluble in water but soluble in non-polar solvents (eg. alcohols, chloroform, ether)
lipids Building block
- True Fats (Triglycerides) = 3 Fatty acids + 1 glycerol
- Phospholipids - 2 fatty acids+ 1 phosphate + 1 glycerol
- Sterols - common in containing ring structures
Types of lipids:
= 3 Fatty acids + 1 glycerol
True Fats (Triglycerides)
- w/o double bond; solid at room temp
eg. Animal fats, beeswax, ear wax
a) Saturated fats
- w/ double bond; remain liquid at room temp
eg. Plant/vegetable oils (olive oil, peanut oil, soya oil, corn oil, etc.)
b) Unsaturated fats
- 2 fatty acids+ 1 phosphate + 1 glycerol
- found in cell membrane of all cells (arranged in bilayer)
- Phospholipids
- common in containing ring structures
eg. Cholesterol, Vitamins ( water- insoluble vitamins
such as Vit. E, Vit. K, Vit A), Progesterone (female
hormone), Testosterone (male hormone)
- Sterols
Source of energy (E)
Stores E
Structural functions
Building blocks of
hormones, vitamins
Insulates the body
Functions of Lipids
= C, H, O, N, some S
Proteins
: amino acids (a.a)
essential a.a.-not synthesized by the body
non-essential a.a.- synthesized by the body
Proteins Building block
–sequence of amino acids (a chain of
polypeptide)
eg. Ala-Lys-Val- Leu-His- Met- Cys
- Primary structure
–interaction between or within
polypeptides
A) α- Helix –eg. keratin
B) β- pleated sheet –eg. fibroin
- Secondary structure
–bending, twisting, coiling of
polypeptides
eg. some antibodies, enzymes
- Tertiary structure
–applies to multimeric
proteins
eg. Hemoglobin in blood
eg. Rubisco (a photosynthetic enzyme in plants
with both tertiary and quaternary
structure)
- Quaternary structure
Source of energy (E)
Stores E
Structural functions
Act as biological catalysts
(enzymes)
Protection from diseases
(antibodies)
Other varied functions depending
on the kind of proteins
Functions of Proteins
= C, H, O, N, P
Nucleic Acids
Nucleic Acids Building block:
Nucleotides
Components of Nucleotide:
- Phosphate (PO4-)
- 5-C sugar
- Nitrogenous Bases
The two-carbon nitrogen ring bases (adenine and guanine) are
purines,
the one-carbon nitrogen ring bases (thymine and cytosine) are
pyrimidines.
Double stranded helix
A, T, C, G as N-bases
genetic material (organism’s
blueprint)
DNA
Single stranded
A, U, C, G as N-bases
needed for making proteins
RNA
- a high energy
carrier
- Adenosine TriPhosphate (ATP)
– transfer energy
eg. Nicotinamide Adenine Dinucleotide (NAD), Flavin Adenine Dinucleotide
(FAD)
- Co-enzymes
Informational macromolecules-
DNA –genetic material
(organism’s blueprint)
RNA –needed for making
proteins
Carry energy (ATP)
Transfer energy (Co-enzymes)
Functions of Nucleic Acids
- Water
- Gases
- Inorganic Salts
- Acids, Bases, Buffers
INORGANIC COMPOUNDS
70-90% by wt.
Universal solvent
Needed for metabolic
processes
Replaces body f luids
Regulates body temperature
- Water
- High boiling point
- High heat capacity
- High heat of vaporization
- High surface tension
- Water Characteristics:
Oxygen (O2) –for maintenance of life (respiration)
Carbon dioxide (CO2) –for manufacturing of food (photosynthesis)
Nitrogen gas (N2) - ???
- Gases
–for maintenance of life (respiration)
Oxygen (O2)
–for manufacturing of food (photosynthesis)
Carbon dioxide (CO2)
–needed by the
body in small amounts (Trace Minerals/ Micronutrients)
Examples:
NaCl (table salt)
Calcium carbonate
Ferrous sulphate
MnSO4
ZnSO4
- Inorganic Salts
–high H+
pH: 1-6
sour taste
litmus: blue to red
eg. Hydrochloric acid (inorganic) –in stomach
citric acid in citrus fruits, acetic acid in vinegar –organic acids
Acids
–high OH-
pH: 8-14
bitter taste
litmus: blue to blue
eg. Soap, baking soda, NaOH
Bases
–a substance or combination of substances that resist change in pH when an acid or a base is added
Eg. Carbonate (H2CO3) –Bicarbonate ion (HCO3-) == found in blood and tissue f luids
Buffers
All organisms are composed of cells
Cell is the smallest functional unit of life
Cells arise from pre-existing cells
The characteristics of an organism
depend on each individual cells
Continuity of characteristics is
maintained through the genetic
material
Energy flow occurs within cells
Modern Cell Theory
“false” nucleus
Naked DNA
No organelles
PROKARYOTE
“true” nucleus
Membrane-bound nucleus
Membrane-bound organelless
eukaryote
Ave 1-2 um in dia.
No nucleus
Without membrane bound organelles
Circular, Naked DNA (nucleiod)
unicellular
Divides by fission
Cytoskeletons absent
Not capable of endocytosis & exocytosis
70S ribosomes
Eg. bacteria, cyanobacteria (BGA), mycoplasmas
Prokaryotic
>10-100 um
With nucleus
With membrane bound organelles
DNA packed in chromosomes
Unicellular/multicellular
Divides by mitosis & meiosis
w/ cytoskeleton
Capable of endocytosis &
exocytosis
80S ribosomes
Eg. plants, animals, fungi, algae,
protozoans
Eukaryotic
• Also called cell/cytoplasmic
membrane
• Fluid (as described by the Fluid
Mosaic Model)
Functions:
1) Regulate the transport of
molecules in & out of the
cell
2) Site of enzyme specific
activity
PLASMA MEMBRANE
For tissue organization
For cell adhesion & cell to cell recognition
CELL COAT
Thick fluid
80% water — containing
amino acids, lipids,
carbohydrates, ions, and
enzymes
Site of many chemical
reactions
Suspends organelles & other
substances
CYTOPLASM
“control center” bec. it
coordinates all the cell’s activities,
which include growth,
intermediary metabolism, protein
synthesis, and reproduction (cell
division).
it stores the cell’s hereditary
material, or DNA
NUCLEUS
– where ribosomes are
produced
Nucleolus
– threadlike
structures inside the nucleus that
carries the genetic material
(where DNA is packed)
Chromosomes
processes, and transports a
wide variety of biochemical
compounds for use inside
and outside of the cell
ENDOPLASMIC RETICULUM
- contains ribosomes
- site of protein synthesis
Rough ER
- w/o ribosomes
- for production of lipids &
hormones
Smooth ER
On the cytoplasm as free ribosomes
and in rough ER
Synthesize proteins
Produced in the nucleolus
RIBOSOMES
also called Golgi body or
Golgi complex
found in both plant and
animal cells
composed of membrane-
covered sacs called cisternae
the packaging and
shipping/distribution
department for the cell’s
chemical products.
GOLGI APPARATUS
double-membraned
site of ATP synthesis via
Cellular Respiration
power generator of the
cell, converting oxygen
and nutrients into
adenosine triphosphate
(ATP)
MITOCHONDRION
gives shape to the cell;
protoplasmic streaming & bldg
blocks of cilia, centriole (direct the
cell during cell division), basal
bodies & flagella (locomotory
structure)
MICROTUBULES
for strength when exposed to
mechanical stress; muscle
contraction
MICROFILAMENTS
maintain cell shape; suspend &
organize organelles; interconnect
cytoskeletal elements & organize
enzymes attached to them
INTERMEDIATE FILAMENTS
- “garbage system”of the cell
- Contain hydrolytic enzymes for
digestion of biomolecules;
protect cell from foreign
materials; digest subcellular
parts as immediate fuel during
cell starvation (“suicidal bag”)
Lysosomes
Peroxisomes - contain enzymes
for oxidation of substances
Glyoxisomes –contain enzymes
for conversion of fats to
carbohydrates
Microbodies
- contain enzymes
for oxidation of substances
Peroxisomes
–contain enzymes
for conversion of fats to
carbohydrates
Glyoxisomes
A newly discovered organelle ( 1990’s)
Cytoplasmic ribonucleoproteins shaped like octagonal
barrels (as the shape of nuclear pore)
Thousands in a cell
Cellular “trucks” – dock at nuclear pores, pick up
molecules synthesized in the nucleus & deliver to
various places in the cell (eg. mRNA to ribosomes for
protein synthesis)
VAULTS
Membranes are composed of
phospholipids and proteins
Membranes are commonly
described as a —
This means that the surface
appears mosaic because of
the proteins embedded in the
phospholipids and fluid
because the proteins can drift
about in the phospholipids
fluid mosaic
Many membrane proteins function as either of the following:
Enzymes
signal transduction
Transport
Because membranes allow some substances to cross or be transported more easily than others, they exhibit —-
Nonpolar molecules (carbon dioxide and oxygen) cross easily
Polar molecules (glucose and other sugars) do not cross easily
selective permeability
- movement of substances from higher to lower concentration
without the expenditure of energy
Example: diffusion of gases in & out of a) blood cell b) plant cell
Simple diffusion
movement of substances across the membrane from higher to lower concentration without the expenditure of energy
random movement of molecules
driven by the Law of Entropy (tendency to move from orderliness to a less ordered state)
Passive Transport
— is a process in which particles spread out evenly in
an available space
Particles move from an area of more concentrated
particles to an area where they are less concentrated
This means that particles diffuse down their concentration
gradient
Eventually, the particles reach equilibrium where the
concentration of particles is the same throughout
Diffusion
Particles move from an area of more concentrated
particles to an area where they are less concentrated
This means that particles diffuse down their —-
concentration
gradient
- movement of substances from higher to lower concentration
without the expenditure of energy & with the aid of transport
proteins (TP)
Example: glucose transport
Facilitated diffusion
— movement of water molecules from higher to lower
concentration without the expenditure of energy
Tonicity is a term that describes the ability of a solution to
cause a cell to gain or lose water
– Tonicity is dependent on the concentration of a
nonpenetrating solute on both sides of the membrane
1. hypertonic - high solute concentration, low water
concentration
2. hypotonic - low solute concentration, high water
concentration
3. isotonic - solute concentration= water concentration
Osmosis
–is a term that describes the ability of a solution to
cause a cell to gain or lose water
–– is dependent on the concentration of a
nonpenetrating solute on both sides of the membrane
1. hypertonic - high solute concentration, low water
concentration
2. hypotonic - low solute concentration, high water
concentration
3. isotonic - solute concentration= water concentration
Tonicity
- high solute concentration, low water
concentration
- hypertonic
- low solute concentration, high water
concentration
- hypotonic
- solute concentration= water concentration
- isotonic
movement of substances across the membrane
against a concentration gradient (from lower to
higher concentration) using energy and with the
aid of transport proteins
Example:
Ca+ – pumped by active transporter across
muscle cell membrane
Na+, H+ = enters the cell by diffusion but
pumped out from the cell by active transport
ACTIVE TRANSPORT
Movement of large substances across the membrane by forming vesicles that fuse with the membrane
BULK TRANSPORT
–is used to import substances useful to the livelihood of the cell
Types:
1. Phagocytosis – “cell-eating” (engulfment)
eg. WBC’s engulf bacteria, amoebas engulf microorganisms
2. Pinocytosis – “cell-drinking”
eg. Kidney cells take up water to maintain fluid balance
3. Receptor-mediated endocytosis – requires the aid of a receptor protein to take up substances
eg. intestinal cells take up large molecules from the inside of gut
Endocytosis
– “cell-eating” (engulfment)
eg. WBC’s engulf bacteria, amoebas engulf microorganisms
- Phagocytosis
– “cell-drinking”
eg. Kidney cells take up water to maintain fluid balance
- Pinocytosis
– requires the aid of a receptor protein to take up substances
eg. intestinal cells take up large molecules from the inside of gut
- Receptor-mediated endocytosis
- is used to export bulky molecules, such as proteins or polysaccharides
eg. Sciatic nerve releases acetylcholine (a neurotransmitter) to initiate muscle contraction
Exocytosis
- the sequence of events in a eukaryotic cell between
one cell division & the next.
THE CELL CYCLE
(“Resting Stage”)
Gap 1 (G1) phase= growth phase 1
Synthesis (S)-phase = most critical stage
Gap 2 (G2) phase= growth phase 2
I.Interphase
(M-phase)/Nuclear Division
- immediately followed by
cytoplasmic division
II.Mitosis
– production of a cell into 2 cells of equal amount of DNA
as the parent cell
- involves mostly somatic cells (body cells)
- produces 2 identical diploid (2n) cells
Mitosis
- reductional cell division
- involves gametes or sex cells in animals (gametic meiosis) or
spores in plants & fungi (sporic meiosis) - produces 4 unidentical haploid (n) cells
- Meiosis
(Karyokinesis)= Mitosis
- follows the Interphase (G1, S-phase, G2)
I. Nuclear Division
( Cytokinesis)
- Immediately follows nuclear division
- it is followed by cell growth
II. Cytoplasmic Division
Nuclear membrane intact
DNA synthesis ( chromosomes are duplicating)
Growth (Gap) phase
Chromatin – highly
dispersed state of DNA
Interphase
– highly
dispersed state of DNA
Chromatin
- Nuclear membrane disintegrating
- Thickening, coiling &
condensation of duplicated
chromosomes - Formation of centriole (in animals)
& spindle fibers (plants & animals)
Prophase
- produces spindle fibers forming astral rays
Centriole
direct the chromosomes during cell division
Spindle fibers-
- Nuclear membrane
disintegrated - Chromosomes align at the
center of the cell - Spindle poles at opposite
ends
Metaphase
- Nuclear membrane still
disintegrated - Sister chromatids separate
& move at opposite poles - Cytoplasmic division is
underway - Formation of cleavage
furrow in animal cell
& primary cell wall in plant
cell
Anaphase
- Nuclear membrane re-forms
- Chromosomes de-condense
characteristic of interphase
Telophase
- fusion of an egg cell & sperm cell
to form a diploid zygote
egg cell + sperm cell ==== zygote
(1n) (1n) (2n)
Fertilization
Maintain constant number of
chromosomes from one generation to
another
Produces variable genes that increases
chance of survival
advantages of meiosis
