The Culture of Science
Science is an intensely social activity, both collaboration (cooperation) and competition characterize scientific culture
All living things share 5 fundamental characteristics
(2 as of now)
1.) All organisms are made up of Cells
4.) All organisms acquire and use Energy
Adenosine Triphosphate (ATP)
The form of chemical energy that is required for reactions to take place inside of the cell.
Cell Theory
The understanding of cells
Theory
a rigorously tested and supported explanation (pattern + process)
Theory of Evolution by Natural Selection
all organisms are made of cells (pattern) and all cells come from preexisting cells (process)
3 theories form the framework for modern biological science:
- The cell theory (Bio. 111) - The theory of evolution by natural selection (Bio.112 and Bio. 211)- The chromosome theory of inheritance (Bio. 111)
How is hereditary information transmitted from one generation to the next?
DNA, chromosomes and genes
Two main types of cells:
Prokaryotes and eukaryotes
Prokaryotes
Domains: Archaea and Bacteria
single-celled
ābefore kernelā
not membrane-bound
ten times smaller than eukaryotes
DNA is not enclosed in the nucleus; in the region called the nucleoid
Eukaryotes
Domain: Eukarya
single-celled or multicellular
ātrue-kernelā
membrane-bound nucleus and organelles
provides more S.A. to move quickly in a large volume
complicated exoskeleton
Broadest phylogenetic classification
Domain
Cell Characteristics
Move,
Metabolize (acquire and use energy),
Respond to the environment,
Reproduce, and
Descend from pre-existing cells, and over time these lineages of cells evolve
Nucleic acids
what chromosomes are made of (genetic information)
Proteins
made by ribosomes that are either free in the cytoplasm or attached
Carbohydrates
provide energy, carbon, identity/ recognition
Lipids
make up the plasma membrane and other structures
Kernel
nucleus
Nucleoid
The central region in a prokaryotic cell where the DNA is located. It is not enclosed by a membrane and is responsible for controlling the cell's activities.
symbiotic
living together with another organism
mutualism
A type of symbiotic relationship where both species benefit from each other's presence.
Plasma membrane
A selectively permeable barrier that surrounds the cell, controlling the movement of substances in and out.
Plasmid
It can replicate independently from the chromosomal DNA and can transfer genetic material between different bacteria. Plasmids often carry genes that provide advantages to the bacteria, such as antibiotic resistance.
Cytoplasm
A gel-like substance found inside cells. It holds organelles in place and facilitates cell processes.
Cell wall
Structure outside the cell membrane that provides support and protection to plant cells.
Ribosome
A cellular structure responsible for protein synthesis. It translates genetic information from DNA into proteins.
NPC,L
Nucleic Acids
Proteins
Carbohydrates
Lipids
The Nucleus
The central part of a cell that contains genetic material
makes up the rRNA for transport and use in the cytoplasm
double membrane (nuclear envelope)
semi-permeable
loosely packed chromosomes
Chromosomes
coiled
only 1
Inside the nucleus with DNA that carries genetic information
made of chromatin
Shape changes as the cell divides
Supercoiled Chromosomes
DNA structure where the double helix is twisted upon itself, forming a tightly coiled shape. (90% of the time)
Relaxed Chromosomes
DNA structure where it is in a linear form. (10% of the time)
Chromatin
The complex of DNA and proteins found in the nucleus of a cell, which condenses to form chromosomes during cell division.
Ribosomes
Made of rRNA and proteins
1 large and 1 small sub-unit. (come together to make proteins)
synthesize proteins in two different locations
free (cytoplasm)
attached ([ER] ore the nuclear envelope)
Endomembrane System
ER - rough and smooth
Golgi apparatus
Lysosomes (animals only)
Continuous or connected by vesicles
Rough ER
Ribosomes bound to it
proteins from ribosomes finish folding here
Lumen
Inside space within the cells organelles
Smooth ER
No attached ribosomes
Synthesizes lipids
Testes and ovaries need lots of this for hormone production
Golgi Apparatus
shipping and receiving center
made of sacs called cisternae
Functions:
the receiving cis side gets vesicles from the ER, forming new cisternae
modifies and manufactures
the shipping trans side sorts and packages materials with molecular barcodes
Cisternae
Membrane sacs found in the ER and Golgi apparatus. They play a crucial role in the processing, modification, and transport of proteins and lipids within the cell.
Lysosome
(animals only)
interior is acidic for digestion
Vacuole
(plants and fungi only)
storage of water and ions
huge, in a fixed place in the cell
can sometimes digest
Peroxisomes
Organelles in which oxidation reactions occur sequestering H2O2 (hydrogen peroxide)
Mitochondria
energy powerhouse of the cell
can make their own proteins because of the DNA and ribosomes it contains
in all eukaryotic cells (fungi, plants, animals, and protists)
double membrane system
produces ATP and oxygen through cellular respiration
Chloroplast
(plants only)
convert sunlight energy into chemical bond energy in the form of carbohydrates
can make their own protein b/c DNA and ribosomes it contains
multiple membranes
Cytoskeleton
Network of protein filaments that give shape, support, and movement to cells. Made up of microtubules, microfilaments, and intermediate filaments.
Actin Filaments
(smallest)
responsible for cytokinesis and cell crawling
Intermediate Filaments
Maintain cell shape and also anchor the nucleus
Microtubule Filaments
(largest)
move chromosomes by building and falling apart at the other end (railroad)
Transmission Electron Microscope (TEM)
Electrons pass through the sample, creating a detailed 2D image
Scanning Electron Microscope (SEM)
Electrons bounce off the sample, creating a 3D sample
Polymerize
to combine or cause to combine to form a polymer.
actions or Ī± and Ī² coming together to form filaments.
Depolymerize
break (a polymer) down intoĀ monomersĀ or other smaller units.
actions or Ī± and Ī² coming breaking apart
Centrosome
(only in animal cells)
organize the microtubules
Microtubule Transport
transport membrane vesicles and organelles through the cytoplasm of eukaryotic cells.
ADP releases
ATP enters
ADP - Pi (hydrolyze)
(repeats)
Centriole
help to arrange the microtubules that move chromosomes during cell division to ensure each daughter cell receives the appropriate number of chromosomes.
ATP Bond Break
Massive amounts of energy are released when one bond is broken in the phosphate group and one inorganic phosphate is released. This results in ADP
ADP
Adenosine Diphosphate
Aquaporins
A type of protein is a part of facilitated diffusion, where lots of water molecules pass through the cell membrane so osmosis can occur faster.
Endosymbiosis
A symbiotic relationship where one organism lives inside the other
The benefit of engulfing a Mitochondrion
Gains energy/ ATP for survival
The benefit of engulfing Chloroplast
Photosynthesis provides sugar, making it advantageous to absorb to engulf to have a food source for the cell.
Polar
partial charge due to unequal sharing of electrons
Nonpolar
no charge, electrons shared equally
Ions
full charge due to the actual GAIN or LOSS of electrons
Phospholipid Bilayer
Acts asĀ a barrier to the passage of molecules and ions into and out of the cell.
Size and charge can affect the diffusion rate across the membrane
contains proteins
Ground Substance
helps the cell resist compression
a part of the extracellular matrix
Fibers
helps the cell resist tension
a part of the extracellular matrix
Extracellular Matrix (ECM)
The ECM provides structural and biochemical support to cells.
Collagen
provides strength and also regulates cell adhesion, supports chemotaxis and migration, and directs tissue development.
a part of the extracellular matrix
Diffusion
the movement of a substance traveling down its concentration gradient
high to low concentration
passive transport
Facilitated Diffusion
molecules going through a protein channel b/c they canāt pass through the semi-permeable membrane if they are charged ions or polar molecules.
Osmosis
Water molecules travel from an area of high concentration to a lower concentration.
movement from low solute concentration to high solute concentration
high water Ļ potential ā Low water Ļ
Hypertonic
high solute concentration
Hypotonic
low solute concentraion
Isotonic
equal solute concentration
Water potential
measurement of potential energy in water
solute and pressure potential
formula - water Ļ = pressure Ļ + solute Ļ
Homeostasis
Stable equilibrium maintained by all living systems
Active Transport
Force molecules to move against their concentration gradient by using ATP/ energy.
Sodium Potassium Pump
To pump sodium out of the cell and potassium onto the cell
3 sodium out
2 potassium in
Resting Membrane Potential
The electric potential energy that results from separating opposite charges across the membrane when those charges aren not stimulating the cell.
Electrochemical Gradient
allow cells to control the direction ions move across membranes
Adjacent Cell Connection (animal)
Tight Junctions
Desmosomes
Gap Junctions
Adjacent Cell Connection (Plant)
Plasmodesmata
connect + direct communication
smooth ER of two cells connect through cell wall
Tight Junctions
forms an adhesion complex between two neighboring cells, serving as a tight seal between the cells
Desmosomes
mediate cell-cell contact and strong adhesion
Requires
membrane proteins
anchoring proteins
intermediate filaments
Gap Junctions
Allows for direct connection and communication, creating open channels between cells.
ex.)heart cells
Most common elements in humans
Hydrogen - H
Oxygen - 02
Carbon - C
Nitrogen - N2
What is circled
Mass number (picture)
What is circled
Atomic number (picture)
Mass #
# of protons + neutrons
Atomic #
# of protons
Valence Electrons
electrons in the outermost shell of an atom
Covalent Bonds
a chemical bond that occurs when atoms share electrons to form electron pairs
Nonpolar Covalent Bonds
atoms share electrons equally
Polar Covalent Bonds
atoms donāt share electrons equally
one atom has more pull, or attraction
Electronegativity
how likely an atom is to attract electrons when forming a chemical bond
FON
Ionic Bonds
made from atoms or ions with a charge
electrons are gained or lost
Hydrogen Bonds
An attraction between two atoms already in chemical bonds.Ā One of the atoms is hydrogen, and the other atom can be anyĀ electronegative atom.