What is science? What is biology
Through its emphasis on objective observation, description, and experimentation, science is a pathway by which we can discover and better understand the world around us.
Biological literacy is essential in the modern world.
Biological issues permeate all aspects of our lives. To make wise decisions, it is essential for individuals and societies to attain biological literacy.
Scientific thinking is a powerful approach to understanding the world.
There are numerous ways of gaining an understanding of the world. Because it is empirical, rational, testable, repeatable, and self-correcting, the scientific method is a particularly effective approach.
Thinking like a scientist: how do you use the scientific method?
The scientific method which is observation, hypothesis, prediction, test, and conclusion, is a flexible, adaptable, and efficient pathway to understanding the world, because it tells us when we must change our belief.
what are the steps of the scientific method?
Make observations, formulate a hypothesis, devise a testable prediction, conduct a critical experiment, draw conclusions & make revisions
Step 1: Make observations
The scientific method begins by making observations about the world, noting apparent patterns or cause-and-effect relationships.
Step 2: Formulate a hypothesis
A hypothesis is a proposed explanation for an observed phenomenon.
Step 3: Devise a testable prediction.
For a hypothesis to be useful, it must generate a testable hypothesis.
Step 4: Conduct a critical experiment.
A critical experiment is one that makes it possible to decisively determine whether a particular hypothesis is correct.
Step 5: Draw conclusions, make revisions.
Based on the results of experimental tests, we can revise a hypothesis and explain the observable world with increasing accuracy. A great strength of scientific thinking, therefore, is that it helps us understand when we should change our minds.
When do hypotheses become theories, and what are theories?
Scientific theories do not represent speculation or guesses about the natural world.
When do hypotheses become theories, and what are theories? part 2
They are hypotheses�proposed explanations for natural phenomena�that have been so strongly and persuasively supported by empirical observation that the scientific community views them as very unlikely to be altered by new evidence.
Controlling variables makes experiments more powerful.
To draw clear conclusions from experiments, it is essential to hold constant all those variables we are not interested in.
Controlling variables makes experiments more powerful. Part 2
Control and experimental groups should differ only with respect to the treatment of interest.
Controlling variables makes experiments more powerful. Part 3
Differences in outcomes between the groups can then be attributed to the treatment.
This is how we do it: Is arthroscopic surgery for arthritis of the knee beneficial?
In a well-controlled experiment, researchers demonstrated that arthroscopic knee surgery for osteoarthritis was no more beneficial for patients - in terms of knee pain and knew functioning - than a placebo surgery.
Repeatable experiments increase our confidence.
Experiments and their outcomes must be repeatable for their conclusions to be considered valid and widely accepted.
We've got to watch out for our biases.
Biases can influence our behavior, including our collection and interpretation of data. With careful controls, it is possible to minimize such biases.
Statistics can help us in making decisions.
Because much variation exists in the world, statistics can help us evaluate whether any differences between a treatment group and a control group can be attributed to the treatment rather than random chance.
Pseudoscience and misleading anecdotal evidence can obscure the truth.
Pseudoscience and anecdotal observations often lead people to believe that links between two phenomena exist, when in fact there are no such links.
How do atoms form molecules?
through bonding
Everything is made of atoms.
Everything around us, living or not, is made up of atoms, the smallest units into which material can be divided without losing its essential properties.
Everything is made of atoms 2
All atoms have the same general structure. They are made up of protons and neutrons in the nucleus, and electrons, which circle far and fast around the nucleus.
An atom's electrons determine whether and how the atom will bond with other atoms.
The chemical characteristics of an atom depend on the number of electrons in its outermost shell.
An atom's electrons determine whether and how the atom will bond with other atoms. part 2
Atoms are most stable and least likely to bond with other atoms when their outermost electron shell is filled to capacity.
Atoms can bond together to form molecules or compounds in how many different ways?
three: Covalent bonds, ionic bonds and hydrogen bonds
Atoms can bond together to form molecules or compounds. Covalent bonds
Covalent bonds occur when atoms share electrons.
Atoms can bond together to form molecules or compounds. Ionic bonds
In ionic bonds, one atom transfers its electrons to another and the two oppositely charged ions are attracted to each other, forming an ionic compound.
Atoms can bond together to form molecules or compounds. Hydrogen bonds
Hydrogen bonds, which are weaker than covalent and ionic bonds, are formed from the attraction between a hydrogen atom and another atom with a slight negative charge.
Water has features that
enable it to support life
Hydrogen bonds make water cohesive.
Water molecules easily form hydrogen bonds, giving water great cohesiveness.
Water has unusual properties that make it critical to life.
The hydrogen bonds between water molecules give water several of its most important characteristics, including cohesiveness, reduced density as a solid, the ability to resist temperature changes, and broad effectiveness as a solvent for ionic and polar su
Living systems are highly sensitive to acidic and basic conditions.
The pH of a fluid is a measure of how acidic or basic the solution is and depends on the concentration of dissolved H+ ions present.
Living systems are highly sensitive to acidic and basic conditions. part 2
Acids, such as vinegar, can donate protons to other chemicals; bases, including baking soda, bind with free protons.
This is how we do it: Do anti-acid drugs impair digestion and increase the risk of food allergies?
Dietary proteins are not digested by the stomach when the stomach's pH is increased as a result of medications taken to treat ulcers, heartburn, and other digestive problems.
Do anti-acid drugs impair digestion and increase the risk of food allergies? part 2
Taking medications for ulcers, heartburn and digestive problems can put people who take anti-acid medications at risk for developing allergic responses to common foods.
Carbohydrates are
fuel for living machines
Carbohydrates include macromolecules that function as fuel.
Carbohydrates are the primary fuel for running all cellular machinery and also form much of the structure of cells in all life forms.
Carbohydrates include macromolecules that function as fuel. part 2
Carbohydrates contain carbon, hydrogen, and oxygen, and generally have the same number of carbon atoms as they do H2O units.
Carbohydrates include macromolecules that function as fuel. part 3
The simplest carbohydrates, including glucose, are monosaccharides or simple sugars and contain from three to six carbon atoms.
Carbohydrates include macromolecules that function as fuel. part 4
As the chemical bonds of carbohydrates are broken down and other more stable bonds are formed, a great deal of energy is released that can be used by organism.
Glucose provides energy for the body's cells.
Glucose is the most important carbohydrate to living organisms.
Glucose provides energy for the body's cells. part 2
Glucose in the bloodstream can be used as an energy source, can be stored as glycogen in the muscles and liver for later use, or can be converted to fat.
Many complex carbohydrates are time-released packets of energy.
Multiple simple carbohydrates are sometimes linked together into more complex carbohydrates.
Many complex carbohydrates are time-released packets of energy. part 2
Types of complex carbohydrates include starch, which is the primary form of energy storage in plants, and glycogen, which is a primary form of energy storage in animals.
Lipids are macromolecules with several functions, including energy storage.
Lipids are insoluble in water and greasy to the touch.
Lipids are macromolecules with several functions, including energy storage. part 2
Lipids are valuable to organisms for long-term energy storage and insulation, in membrane formation, and as hormones.
Cholesterol and phospholipids are used to build sex hormones and membranes.
Cholesterol and phospholipids are lipids that are not fats.
Cholesterol and phospholipids are used to build sex hormones and membranes. part 2
Both are important components in cell membranes.
Cholesterol and phospholipids are used to build sex hormones and membranes. part 3
Cholesterol also serves as a precursor to steroid hormones, important regulators of growth and development.
Proteins are
versatile macromolecules that serve as building blocks
Proteins are bodybuilding macromolecules.
Unique combinations of 20 amino acids give rise to proteins, the chief building blocks of the physical structures that make up all organisms.
Proteins are bodybuilding macromolecules. part 2
Proteins perform myriad functions, from assisting chemical reactions to causing blood clotting to building bones to fighting microorganisms.
A protein's function is influenced by its three-dimensional shape.
A protein's particular amino acid sequence determines how it folds into a particular three-dimensional shape.
A protein's function is influenced by its three-dimensional shape. part 2
This shape determines many of the protein's properties, such as the molecules it will interact with.
A protein's function is influenced by its three-dimensional shape. part 3
When a protein's shape is deformed, the protein usually loses its ability to function.
Enzymes are proteins that speed up chemical reactions.
Enzymes are proteins that help initiate and speed up chemical reactions.
Enzymes are proteins that speed up chemical reactions. part 2
Enzymes aren't permanently altered in the process, but rather can be used again and again.
Nucleic acids store information on
how to build and run a body.
Nucleic acids are macromolecules that store information.
The nucleic acids DNA and RNA are macromolecules that store information in their unique sequences of bases contained in nucleotides, their building-block molecules.
Nucleic acids are macromolecules that store information. part 2
Both nucleic acids play central roles in directing protein production in organisms.
DNA holds the genetic information to build an organism.
DNA is shaped like a ladder in which the long vertical sides of the ladder are made from a sequence of sugar-phosphate-sugar-phosphate molecules and the rungs are pairs of nucleotide bases.
DNA holds the genetic information to build an organism. part 2
The sequence of nucleotide bases contains the information about how to produce a particular protein.
RNA is a universal translator, reading DNA and directing protein production.
RNA acts as a middleman molecule�taking the instructions for protein production from DNA to another part of the cell where, in accordance with the RNA instructions, amino acids are linked together into proteins.
What is a cell
the smallest unit of life that can function independently and perform all of the necessary functions of life, including reproducing itself
All organisms are made of cells
The most basic unit of any organism is the cell, the smallest unit of life that can function independently and perform all of the necessary functions of life, including reproducing itself.
All organisms are made of cells. part 2
All living organisms are made up of one or more cells, and all cells arise from other, pre-existing cells.
Prokaryotic cells are structurally simple but extremely diverse.
Every cell on earth is either a eukaryotic or a prokaryotic cell.
Prokaryotic cells are structurally simple but extremely diverse. part 2
Prokaryotes, which have no nucleus, were the first cells on earth.
Prokaryotic cells are structurally simple but extremely diverse. part 3
They are all single-celled organisms.
Prokaryotic cells are structurally simple but extremely diverse. part 4
Prokaryotes include the bacteria and archaea and, as a group, are characterized by tremendous metabolic diversity.
Eukaryotic cells have compartments with specialized functions.
Eukaryotes are single-celled or multicellular organisms consisting of cells with a nucleus that contains linear strands of genetic material.
Eukaryotic cells have compartments with specialized functions. part 2
The cells also commonly have organelles throughout their cytoplasm; these organelles may have originated evolutionarily through endosymbiosis or invagination, or both.
Cell membranes are
gatekeepers
Every cell is bordered by a plasma membrane.
Every cell of every living organism is enclosed by a plasma membrane, a two-layered membrane that holds the contents of a cell in place and regulates what enters and leaves the cell.
Molecules embedded in the plasma membrane help it perform its functions.
The plasma membrane is a fluid mosaic of proteins, lipids, and carbohydrates.
Molecules embedded in the plasma membrane help it perform its functions. part 2
Proteins found in the plasma membrane enable it to carry out most of its gatekeeping functions.
Molecules embedded in the plasma membrane help it perform its functions. part 3
The proteins act as receptors, help molecules enter and leave the cell, and catalyze reactions on the inner and outer cell surfaces.
Molecules embedded in the plasma membrane help it perform its functions. part 4
In conjunction with carbohydrates, some plasma membrane proteins identify the cell to other cells.
Molecules embedded in the plasma membrane help it perform its functions. part 5
In addition to the phospholipids that make up most of the plasma membrane, cholesterol is an important lipid in some membranes, influencing fluidity.
Membrane surfaces have a "fingerprint" that identifies the cell.
Every cell in your body has a "fingerprint" made from a variety of molecules on the outside-facing surface of the cell membrane.
Membrane surfaces have a "fingerprint" that identifies the cell. part 2
This molecular fingerprint is key to the function of your immune system.
Molecules move across membranes
in several ways.
Passive transport is the spontaneous diffusion of molecules across a membrane.
For proper functioning, cells must acquire food molecules and/or other necessary materials from outside the cell.
Passive transport is the spontaneous diffusion of molecules across a membrane. part 2
Similarly, metabolic waste molecules and molecules produced for use elsewhere in the body must move out of the cell.
Passive transport is the spontaneous diffusion of molecules across a membrane. part 3
In passive transport�which includes simple and facilitated diffusion and osmosis�the molecular movement occurs spontaneously, without the input of energy.
Passive transport is the spontaneous diffusion of molecules across a membrane. part 4
This generally occurs as molecules move down their concentration gradient.
Osmosis is the passive diffusion of water across a membrane.
The diffusion of water across a membrane is a special type of passive transport called osmosis.
Osmosis is the passive diffusion of water across a membrane. part 2
Water moves from an area with a low concentration of solutes to an area with a higher concentration of solutes.
Osmosis is the passive diffusion of water across a membrane. part 3
Water molecules move across the membrane until the concentration of water inside and outside the cell is equalized.
In active transport, cells use energy to move small molecules into and out of the cell.
In active transport, movement of molecules across a membrane requires energy.
In active transport, cells use energy to move small molecules into and out of the cell. part 2
Active transport is necessary if the molecules to be moved are very large or if they are being moved against their concentration gradient.
In active transport, cells use energy to move small molecules into and out of the cell. part 3
Proteins embedded in the plasma membrane act like motorized revolving doors to actively transport (pump) the molecules.
Endocytosis and exocytosis are used for bulk transport of particles.
When materials cannot get into a cell by diffusion or through a pump ,for example, when the molecules are too big, cells can engulf the molecules or particles with their plasma membrane in a process called endocytosis.
Endocytosis and exocytosis are used for bulk transport of particles. part 2
Similarly, molecules can be moved out of a cell by exocytosis.
Endocytosis and exocytosis are used for bulk transport of particles. part 3
In both processes, the plasma membrane moves to surround the molecules or particles and forms a little vesicle that is pinched off inside the cell (endocytosis) or fuses with the plasma membrane and dumps its contents outside the cell (exocytosis).
How many important landmarks distinguish eukaryotic cells?
Nine
The nucleus is the cell's genetic control center.
The nucleus is usually the largest and most prominent organelle in the eukaryotic cell.
The nucleus is the cell's genetic control center. part 2
It directs most cellular activities by controlling which molecules are produced and in what quantity.
The nucleus is the cell's genetic control center. part 3
The nucleus is also the storehouse for hereditary information.
Cytoplasm and the cytoskeleton form the cell's internal environment, provide its physical support, and can generate movement.
The inner scaffolding of the cell, which is made from proteins, is the cytoskeleton.
Cytoplasm and the cytoskeleton form the cell's internal environment, provide its physical support, and can generate movement. part 2
Consisting of three types of protein fibers�microtubules, intermediate filaments, and microfilaments�the cytoskeleton gives animal cells their shape and support
Cytoplasm and the cytoskeleton form the cell's internal environment, provide its physical support, and can generate movement. part 3
The cytoskeleton also gives cells some ability to control their movement, and serves as a series of tracks on which organelles and molecules are guided across and around the inside of the cell.
Mitochondria are the cell's energy converters.
In mitochondria, which are found in nearly all eukaryotic cells, the energy contained in the chemical bonds of carbohydrate, fat, and protein molecules is converted into carbon dioxide, water, and ATP, the energy source for all cellular functions and acti
Mitochondria are the cell's energy converters. part 2
Mitochondria may have their evolutionary origins as symbiotic bacteria living inside other cells.
The cell wall provides additional protection and support for the plant cells.
The cell wall is an organelle found in plants, and in some other non-animal organisms.
The cell wall provides additional protection and support for the plant cells. part 2
It is made primarily from the carbohydrate cellulose, and it surrounds the plasma membrane of the cell.
The cell wall provides additional protection and support for the plant cells. part 3
The cell wall confers tremendous structural strength on plant cells, gives plants increased resistance to water loss, and provides some protection from insects and other animals that might eat the plant.
The cell wall provides additional protection and support for the plant cells. part 4
In plants, plasmodesmata connect cells and enable communication and transport between them.
Chloroplasts are the plant cell's power plant.
The chloroplast is the organelle in plants and algae that is the site of photosynthesis�the conversion of light energy into chemical energy, with oxygen as a by-product.
Chloroplasts are the plant cell's power plant. part 2
Chloroplasts may have originally been bacteria that were engulfed by a predatory cell by endosymbiosis.
These molecules maintain pH by absorbing or releasing H+ ions.
Buffers
The four most abundant elements ("The Big Four") in living organisms are...
Hydrogen, Carbon, Oxygen, Nitrogen
This type of chemical bonding gives water its special properties, such as cohesion and adhesion.
Hydrogen Bonding
This macromolecule functions in the catalyzing of chemical reactions.
Enzyme
Glucose that circulates in your blood has one of three fates:
it is used to fuel cellular activities (to make ATP)
it can be converted into fat for long term storage ???
It can be temporarily stored as glycogen
Scientists use observations and data to form and test.....
Hypotheses
In a scientific experiment, this variable can be compared with an experimental group to assess whether one particular variable is causing a change in the experimental group.
Control group
The set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather is called....
Statistics
This is the frequently observed, poorly understood, phenomenon in which people tend to respond favorably to any treatment.
Placebo Effect
What term describes when only a few observations or data points appear to reveal links between two phenomena that do not actually exist.
Anecdotal Evidence
What cell structure is responsible for controlling movement of substances into and out of a cell?
Plasma or cell membrane
This type of cell has NO nucleus or membrane-bound organelles
Prokaryotic
True or False?
Eukaryotic organisms can be either unicellular or multicellular.
True
If you put a cell into an hypotonic solution, what will happen?
It will swell
Give two examples of active transport.
Primary or secondary transport (pumps). Endocytosis and Exocytosis
Cellular respiration occurs within WHAT organelle of a cell?
Mitochondrion
Photosynthesis occurs within WHAT organelle of a cell?
Chloroplast
Name this process:
CO2 + H2O + light = sugar + O2
Photosynthesis
If oxygen is NOT present, cellular respiration will not occur. What is the other process by which organisms generate energy?
Fermentation
ATP is generated during cellular respiration. Where does the energy come from to form this molecule?
By breaking the bonds within glucose
This molecule is produced during cellular respiration and drives cellular metabolism.
Adenosine Triphosphate
ATP
This macromolecule is stored within the nucleus of cells and contains genetic information.
BE SPECIFIC!
Deoxyribonucleic Acid
DNA
Molecules are groups of atoms _______________ bonded together.
Covalently
What is the purpose of photosynthesis?
To make food/glucose
Which of the following is NOT a function of proteins?
A. Component of plasma membranes
B. Long term high energy storage
C. Catalyzes chemical reactions
D. Protection against disease
Long term high energy storage
What are four components of a critical experiment?
Controlling variables
Avoiding bias
Randomized
Repeatable