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means "staying the same".
Homeostasis is how our bodies stay in balance.
An increase in size of an organism
Also the number of cells for an organism
The changes that take place between conception and death.
The discipline of identifying and classifying organisms according to specific criteria.
A group of techniques use t study and investigate phenomena, test theories, etc.
- Steps in Scientific Method
- 1. Observation
- observe what it is that you are going to studying.
- 2. Hypothesis
- A tentative explanation for what the scientist has observed.
- 3. Experiment/Further Observation
- Experiments are used to test a hypothesis. Good experiments should always include controls.
- 4. Conclusion
- Scientists analyze the data they collect in their experiments to reach a conclusion.
- Often leads to a hypothesis or another experiment.
What are the 7 characteristics that all life share?
2. Acquire materials and energy
4. Respond to stimuli
5. Are homeostatic
6. Grow and develop
7. Have the capacity to adapt.
What are the 3 domains of organisms?
1. Archaea- Bacteria that can live in extreme conditions.
3. Eukarya- All other organisms that are not bacteria
Eukarya's 4 kingdoms.
1. Protista- All the leftovers
2. Fungi- Help decompose dead organisms
3. Plantae- Multicellular photosynthesizers (make their own food)
4. Animalia- Multicellular ingesters
The smallest functional units of matter
Atoms with a positive charge
Atoms with a neutral charge
Atoms with a negative charge
Basic structure of an atom
Protons and neutrons in the nucleus and electrons circling the nucleus of the atom
The number of protons in an atom
The number of protons and neutrons in the atom
Used to describe the need to have 8 electrons in the outer shell
When atoms share a pair of electrons between them to make them have full outer shells
Drawn as lines between atoms
Atoms that give up an electron (when they have only one in their outer shell) and give it to another atom that needs one ( they have 7 in their outer shell)
Form when a hydrogen molecule from one molecule becomes attracted to an electronegative atom of another molecule (such as nitrogen and oxygen atoms)
Depicted as a dash mark between atoms
Bond between two atoms in which electrons are shared unequally. Because of this, one end of the bond has a fractional negative charge and the other a positive charge.
A type of covalent bond in which both atoms attract the bonding electrons equally or nearly equally.
Molecules that have a significant number of polar bonds
Molecules that are composed of mostly nonpolar bonds
When an atom gains or loses an electron it will acquire a charge
Substances that are dissolved in liquids
The liquid solutes are dissolved in
Polar molecules will dissolve readily in water
Non polar molecules do not dissolve readily in water.
Molecules that release H+
A pH less than 7 is acidic
Molecules that accept H+
A pH of more than 7 indicates that a solution is basic or alkaline
neutral pH is 7
4 things pH can affect
1. The shapes and functions of molecules
2. The rates of chemical reactions
3. The ability of two molecules to bind
4. The ability of ions or molecules to dissolve in water.
4 macromolecules of life
Carbohydrates, lipids, proteins, nucleic acids
Made of carbon, hydrogen, and oxygen.
Molecules that are composed of hydrogen and carbon atoms.
Nonpolar and insoluble in water.
Include fats, phospholipids, and steroids.
Composed of carbon, hydrogen, oxygen, and nitrogen (has lots of nitrogen)
Are responsible for the storage, expression, and transmission of genetic material
The simplest sugars
Most common types have five carbons (pentose) and six carbons (hexose)
Two monosaccharides that join together
When many monosaccharides join together
The building blocks of proteins
There are 20 amino acids
Cells with a relatively simple structure.
They DO NOT have a membrane bound nucleus
Second cell type.
These include some single-celled animals, fungi, plants, and animals
Have many different organelles.
Subcellular compartments (membrane-bound) that have their own unique structure and function.
What do Eukaryotes and Prokaryotes have in common?
1. Plasma membrane
Contains many different organelles.
The synthesis and breakdown of molecules takes place in the ctoplasm
Enclosed by a double membrane called the nuclear envelope.
In most cells, the nucleus is very large and occupies 10-2% of the volume.
Endoplasmic Reticulum (ER)
A convoluted network of membranes that form flattened, fluid-filled tobules.
Can have ribosome attached (rough ER)
Smooth ER lacks ribosomes.
Stacks of flattened sacs that are not attached to each other. Packages materials into secretory vesicles that then fuse with the plasma membrane, releasing their contents to the outside of the cell.
Cis Golgi are found nearest the ER and the trans Golgi are found nearest the plasma membrane
Provides a boundary between the internal and external environments. Separates inside of cell from the outside.
Cells are surrounded by a plasma membrane. Important in cell signaling.
Has an outer and inner membrane.
Known as cells power supply
Primary role is to make adenosine triphosphate (ATP) and also generates heat in brown fat cells.
Specialized organelles that capture the sun's energy
Solute concentrations are the same inside the cell as outside
Solute concentration is higher outside the cell than inside
Water will rush out of the cell and it will shrink
Solute concentration is higher inside the cell than outside
Water rushes into the cell and it will swell and burst
The movement of water across membranes to balance solute concentrations
The movement of molecules down a concentration gradient
They will move from an area of high concentration to low concentration until equilibrium is achieved
The plasma membrane exists as a phospholipid bilayer
The phospholipids arrange themselves in a very particular fashion
Their polar heads face the inside and outside of the cell while the hydrophobic tails face each other in the middle of the membrane
Allow molecules to pass through membranes
Also allow molecules to pass through membranes but they work differently than channels
These selectively interact with a molecule or ion so that it can pass across the membrane
Have shape that allows specific molecules to bind
When the molecule binds to the receptor, it changes shape and brings about a cellular response
The concentration of a solute will be higher on one side or the other (intra- vs extracellularly)
Gradients can involve ions–these can be both chemical and electrical
This means that the net charge can be higher on one side of the membrane as well as having higher concentrations of a particular charged ion higher on one side
How do molecules move?
Molecules want to go from an area of high concentration to an area of low concentration
This is called moving down a gradient
The 3 ways that material can be brought into cells
1. Receptor-mediated endocytosis
This involves proteins on the surface called receptors that bind to specific cargo
Many receptors will aggregate and this causes formation of the protein coat
The plasma membrane to invaginate and eventually pinch off into a vesicle that will then take the cargo to its destination
The process by which material is brought inside the cell from the external environment
A process by which material inside the cell is excreted into the extracellular environment
Material is packaged into vesicles for transport
Most of the time, the vesicles are derived from the Golgi
3 things all nucleotides possess
1. A phosphate group
2. A sugar called deoxyribose
- 3. One of four possible bases
- The four bases are:
- adenine (A), thymine (T), cytosine (C), guanine (G)
How do the bases (of nucleotides) bond together?
A always binds with T
G always binds with C
DNA replication summary
The DNA must first be unwound –the enzyme that does this is called helicase
It pulls apart the DNA parental strands (imagine unzipping a zipper)
Next, an enzyme called DNA polymerase moves along the DNA strand and adds the right nucleotides from its pool of four different nucleotides (it matches by using the parental strand!!)
When replication is complete, the two sets of DNA (each having a parental strand and a daughter strand) will wind up into the double-helix
3 ways RNA is different from DNA
1. RNA is single stranded
2. RNA has the sugar ribose instead of deoxyribose
3. RNA contains the base uracil (U) in place of thymine (T) so in RNA, A always binds with U!!!!
A stretch of DNA that encodes the instructions for making protein
The general rule is that a single gene codes for a single protein
Basic unit of genetic code: a unit in messenger RNA consisting of a set of three consecutive nucleotides that specifies a particular amino acid in protein synthesis
What is the difference between transcription and translation?
Translation is the process that converts an mRNA message into a polypeptide.
Transcription is the process of copying a sequence of DNA to produce a complementary strand of RNA.