Science and Experiments
1. The variable that is the subject of the experiment:
2. The variable that is the data or results of the experiment:
3. Variables that are kept the same between the groups in an experiment:
1. independent variable
2. dependent variable
3. controlled variables
Identify three things that all graphs should have.
descriptive title
labeled axes
units on each axis
consistent scale on each access
legend/key for multi-line graphs
Why is carbon the molecular backbone of all the biomolecules?
Carbon's valence electrons make 4 bonds which allows carbon-based molecules to be very large and very complex structurally.
Identify three cell structures found in both prokaryotic and eukaryotic cells, only one of which can be a biomolecule.
Ribosomes, cytosol, plasma membrane and all of the 4 biomolecules
All of the controlled chemical reactions that occur in an organism is called what?
Identify an anabolic pathway and a catabolic pathway.
metabolism
anabolic pathway --> photosynthesis, protein synthesis, chemosynthesis
catabolic pathway --> digestion, cellular respiration
How many independent variables are typically investigated in an experiment?
one
1. The _______ is the average of the values in a data set.
2. The _______ is the value that occurs most frequently in a data set.
3. The ________ is the middle value in a data set.
4. The ________ is the difference between the smallest and largest value in a data set.
mean
mode
median
range
Identify water's most fundamental chemical property and explain how it leads to its other important properties.
Water is a polar molecule which means its electrons are not distributed evenly. This causes water molecules to constantly make hydrogen bonds with themselves and other molecules, leading to its other important properties.
The plasma membrane is composed of _________ which are _________ because they have a _________ (water repelling) tail and a __________ (water attracting) head.
phospholipids
amphipathic
hydrophobic
hydrophilic
Explain what enzymes are and why they're so important for life.
Enzymes are a type of protein that act as biological catalysts. This means that they speed up chemical reactions by lowering the activation energy required to get the reaction started. None of the metabolic reactions that keep organisms alive would be possible without enzymes.
The experimental group is the main subject of the experiment since it receives the independent variable. The control group does not receive the independent variable and is used as a basis of comparison with the experimental group.
When analyzing data in science, what do the following terms refer to?
N = __________
n = __________
S = __________
N = whole population
n = sample population/specific data set from the whole population
S = standard deviation
Explain the connection between the 6 elements essential for life (CHNOPS) and the 4 biological macromolecules (carbohydrates, lipids, proteins, nucleic acids).
The 6 elements essential for life combine together in different amounts and arrangements to make the 4 biological macromolecules.
Identify what large category of cells contain an endomembrane system and briefly describe its function.
Identify three organelles that are part of this system.
The endomembrane system acts like a transportation system within eukaryotic cells, moving around important biomolecules like proteins and lipids.
nuclear membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, plasma membrane
Correct the following statement.
Our cells directly use the energy from food to do cellular work.
Our cells use the energy from food to create ATP through cellular respiration, which can then be used to do cellular work.
What is wrong with the following hypothesis?
Every person has an invisible spirit that reflects their true moral character, but it can never be detected by any instrument or observation.
This hypothesis is not testable. Hypotheses are testable explanations. Typically, the results of experiments or observations are the way in which hypotheses are tested.
Identify the best type of graph to use for each data set description below:
1.discrete, categorical data
2. continuous data
3. correlation between two measured variables
4. frequency of a single variable
5. Comparing different data sets in a single graph
6. percentages of a whole
1. bar graph
2. line graph
3. scatter plot
4. histogram
5. box-and-whisker plot
6. pie graph
Identify the four biomolecules and briefly describe a main function of each.
carbohydrates: short term energy storage, structure in plants
lipids: long term energy storage, insulation, cell membrane structure, hormone structure
proteins: enzymes, signaling molecules, cell transport and movement, structural framework, immune system function, muscle contraction
nucleic acids: genetic information storage
Identify and briefly describe the main types of cell transport.
Simple diffusion -- movement of particles down/with their concentration gradient without energy.
Facilitated diffusion -- movement of particles down/with their concentration gradient with protein assistance but no energy
Active transport -- movement of particles against their gradient with protein assistance and with energy
Identify the function of the following molecules in cellular respiration:
glucose
FADH2
NADH
ATP
glucose: sugar molecule that is broken down to release energy
FADH2: electron carrier that take electrons from glucose to electron transport chain
NADH: same as FADH2
ATP: energy molecule that is made through cellular respiration and used by cells to do work
Define the following science word roots:
endo =
auto =
lysis =
cyto =
di =
endo = inside/within
auto = self
lysis = to burst/break
cyto = cell
di = two/double
Briefly explain the difference between standard deviation and standard error.
Standard deviation is a measure of the spread within a data set and standard error is a measure of how precisely a data set matches the larger population from which it comes.
Identify three structural differences between DNA and RNA.
DNA: very long, double-stranded, contains deoxyribose sugar and the nitrogen base thymine
RNA: short, single-stranded, contains ribose sugar and the nitrogen base uracil (and not thymine)
1. Describe the relationship between surface area and volume that most cells must maintain and why it is critical for their survival.
2. If a cell or cell projection must be long, which shape works best?
1. Cells must maintain a high surface area to volume ratio (big surface area, small volume) in order to allow rapid movement of molecules and rapid removal of waste products.
2. cylinder (examples: neurons, muscle fibers, cilia)
Briefly describe two similarities between the electron transport chains in photosynthesis and cellular respiration.
They both use electron carriers.
They both use energy from movement of electrons to pump hydrogen ions across a membrane to create a gradient.
They both rely on a concentration gradient of hydrogen ions to power ATP synthase which makes ATP through the process of chemiosmosis.