Key Concepts Flashcards
(60 cards)
What is science?
-Science is both a body of knowledge and a process.
-It involves studying the natural world, which like biology focuses on living organisms.
-Science involves the following things:
1) Observation: Noticing something interesting or unusual. This leads us to our hypotheses, as the hypotheses are the proposed explanations for those observations.
2) Hypothesis Formation: Proposing an explanation based on imagination, intuition, logic, and previous knowledge.
3) Testing: Conducting experiments to evaluate the hypothesis.
4) Modification: Adjusting the hypothesis based on test results.
What characteristics does a scientific hypotheses require?
-A scientific hypotheses must be testable and falsifiable, meaning that it should have the possibility of being proven wrong through observation.
-Hypothesis testing is based on deductive reasoning: a general principle to predict an expected observation.
-The steps to creating a hypothesis are as follows:
1) Hypotheses that is testable and falsifiable
2) Make prediction
3) Test prediction
What are independent variables and dependent variables?
-Independent Variable: This is the variable that scientists manipulate or change to observe its effects. It is the factor that can be freely altered during the experiment. For example, if researchers are studying the effect of Vitamin C on cold prevention, the amount of vitamin C intake would be the independent variable.
-Dependent Variable: This variable is what scientists measure in the experiment. It is the outcome that may be affected by changes in the independent variable. In the vitamin C study, the dependent variable would be the indvidiuals’ susceptibility to illness upon exposure to a cold virus.
What are controlled experiments in hypothesis testing?
-Controlled experiments involve comparing an experimental group with a control group.
-The goal is to test hypotheses by ensuring that the only difference between the groups is the experimental treatment.
-This helps eliminate alternative hypotheses and isolate the effect of the treatment.
What two things are needed for controlled experiments?
1) Random Assignment: Subjects are randomly assigned to either the control group or the experimental group. This randomization helps ensure that the groups are as similar as possible, minimizing differences that could affect the results. For example, in a study on echinacea tea, participants were randomly assigned to groups to ensure a balanced representation of the population.
2) Identical Participation: Both groups should participate under identical conditions, except for the experimental treatment. This means that all participants receive the same information and undergo the same procedures, with the only difference being the treatment itself. In the echinacea study, both groups drank tea, but only the experimental group received tea with echinacea extract, while the control group received a placebo or “sham tea.”
What is the gold standard of hypotheses testing?
-Double-blind, placebo-controlled and randomized experiments are the gold standard.
-Double blind means that neither the participants nor the researchers know who is receiving the treatment or the placebo. This helps prevent bias from influencing the results.
-Placebo-controlled means that a placebo is used to ensure that any effects observed are due to the treatment itself and not participants expectations.
-Randomized means that participants are randomly assigned to either the treatment or control group, ensuring that the groups are comparable.
What are model systems?
-Model systems are alternative organisms used to test hypoetheses that would be impractical or unethical to test on humans.
-This involves testing on bacteria, nematodes, mammals(rodents, dogs, pigs, human cells).
What do statistical tests tell us in science?
-Statistical tests help to evaluate the likelihood that observed differences between experimental and control groups are not random.
-Statistical tests do carry the limitation that statistical significance does not equate to practical significance. A finding may be statistically significant, but not have meaningful applications in real world context.
-Applications may be limited. Just because a result is statistically significant, doesn’t mean it will change medical advice.
What are the eight key characteristics of life?
1) Common Set of Biological Molecules: All living organisms contain essential biological molecules, such as proteins, lipids, carbohydrates, and nucleic acids, which are crucial for various cellular functions.
2) Composed of Cells: The cell is the basic structural and funcitonal unit of life.
3) Growth: Living organisms exercising their ability to grow often involves an increase in size and number of cells.
4) Movement: While not all organisms move in the same way, movement is a common characteristic.
5) Reproduction: The ability to reproduce and pass genetic information.
6) Responses to External Environmental Stimuli: Organisms can respond to changes in their environment, which is crucial for survival.
7) Metabolism: This encompasses all chemical processes within cells, including energy production and waste excretion.
8) Maintain Homeostasis: Organisms regulate their internal environment to maintain stable conditions necessary for life, despite external changes.
What is a molecule?
A molecule is two or more atoms held together by chemical bonds.
What are macromolecules?
-Macromolecules are large organic molecules composed of smaller subunits. In living organisms, the primary macromolecules include:
1) Carbohydrates
2) Proteins
3) Lipids
4) Nucleic acids.
What are carbohydrates?
-Carbohydrates are essential for energy storage and structural functions.
-Carbohydrates are made of molecules of carbon, oxygen, and hydrogen.
-They can be simple sugars like monosaccharides or complex structures like polysaccharides, which consist of sugar monomers linked by covalent bonds.
-Monosaccharide means 1 sugar, while disaccharides means 2 sugars. Polysaccharides means many sugars.
What are proteins?
-Proteins perform many important functions in cells. They catalyze reaction, and serve as transport channels or chemical messengers.
-Proteins are made of carbon, oxygen, hydrogen, and nitrogen.
-They are made up of amino acids.
-There are 20 standard amino acids that can be used as building blocks to make all proteins in living organisms.
-Amino acids are joined by peptide bonds.
What are lipids?
-Lipids are crucial for storing energy and forming cell membranes.
-Lipids are composed mostly of carbon and hydrogen.
-They are typically composed of fatty acids and glycerol.
What are nucleic acids?
-Nucleic acids include DNA and RNA, which are vital for storing and transmitting genetic information.
What are cells? What are the different types of cells? How do plant and animal cells differ?
-Cells are the smallest, most basic unit of life.
-Cells are microscopic, self-contained units enclosed by a water-repelling membrane.
-The human body has 100 trillion cells.
-There are prokaryotic cells and eukaryotic cells.
-Prokaryotic cells lack a nucleus and are membrane-bound organelles. They are typically smaller and simpler, with ribosomes, a cell wall, a cell membrane, and a nucleoid region. Bacteria are common examples of prokaryotic organisms.
-Eukaryotic cells have a nucleus, the cell membrane, and various membrane-bound organelles, such as mitochondria and the endoplasmic reticulum. Eukaryotic cells are fund in plants, animals, fungi, and protists.
-Plant cells have a cell wall, chloroplasts, and large central vacuole.
-Animal cells lack a cell wall, chloroplasts, and have small multiple vacuoles. Instead, they have centrioles, which are involved in cell division?
Compare and contrast prokaryotes and eukaryotes?
1) Prokaryotes are small and microscopic, while eukaryotes are larger, and often single-celled or multicellular.
2) Prokaryotes are simple, while eukaryotes are complex.
3) Prokaryotes have genetic material, but not nucleus, while eukaryotes hold their genetic material inside their nucleus.
4) Prokaryotes don’t have organelles, while eukaryotes have membrane-bound organelles.
5) All prokaryotes have cell walls, while only some eukaryotes have cell walls.
Are viruses alive?
-Answering the question is difficult.
-Variuses exist in a gray area between the living and nonliving.
-Viruses must replicate within a host cell.
-Viruses are active agents of evoluation and often exchange genetic information with their hosts.
-Viruses may add their genes to the genome of their hosts, possibly becoming a critical part of the host.
-Viruses are not living due to their lack of cellular structure, dependence on host cells, absence of metabolic processes, and their structure(a virus typically consists of a strand of DNA or RNA encased in a protein shell, known as a capsid).
What is metabolism?
-Metabolism encompasses all the chemical processes that occur within cells. These processes include the following:
1) Energy Production: Metabolism involves breaking down substances to produce energy. This energy is crucial for various cellular activities and overall bodily functions.
2) Synthesis of Necessary Substances: It also includes the synthesis of compounds needed for life, such as proteins and nucleic acids.
3) Waste Excretion: Metabolic processes generate waste products, which must be excreted to maintaining cellular health.
What are enzymes?
-Enzymes are proteins that play a crucial role in metabolism by catalyzing, or speeding up chemical reactions in cells. Their key functions are as follows:
1) Catalysis: Enzymes lower the activation energy required for reactions, allowing them to occur more easily and without the need for excessive heat, which may damage cells.
2) Specificity: Each enzyme is specific to a particular reaction, determined by the shape of its active site and the substrate it binds to. This specificity ensrues that enzymes only catalyze the intended reactions.
3) Function: Enzymes can break down substances, such as food molecules, to release energy, or they can build complex molecules, to release energy, or they can build complex molecules from simpler ones.
4) Reusability: After catalyzing a reaction, enzymes are not permanently altered and can be used repeatedly.
What are the three key components of cells?
1) Cell Structure
2) Energy for Cells to Work
3) Cancer: cell growth out of control
What does the cell structure consist of?
-The cell structure includes the cytoplasms, cytosol, and organelles.
-Cytoplasm: A crucial component of the cell, encompassing both the cytosol and organelles. It acts as the medium where cellular processes occur.
-Cytosol: This is the watery matrix within the cytoplasm. It contains salts and enzymes necessary for cellular reactions and serves as the environment necessary for cellular reactions and serves as the environment.
-Organelles: These are specialized structures within the cell, each performing specific functions similar to how organs function in the body.
-There is the Nucleus that houses DNA. There is the mitochondria that is involved in energy production. Ribosomes are sites for protein synthesis. The Golgi Apparatus modifies and sorts proteins. Lysosomes are responsible for breaking down macromolecules.
What are the subcellular structures?
1) Cell Wall
2) Nucleus
3) Nucleolus
4) Mitochondrion
5) Chloroplast
6) Lysosome
7) Ribosomes
8) Rough endoplasmic reticulum
9) Smooth endoplasmic reticulum (smooth ER)
10) Golgi apparatus
11) Centrioles
12) Cytoskeletal elements
13) Central vacuole
What does the cell wall do?
-The cell wall is found in plant cells, fungi, and some bacteria.
-It is located outside the plasma membrane.
-It provides protection and structural support.
-The cell wall is composed primarily of cellulose, a polysaccharide that forms strong fibers.
