Science Fall 2014 Semester Exam Review
There are 65 multiple choice questions and 5 short answers on the test.
Safety and scientific method:
 Wear safety goggles at all the times when you are working with glass, fire, or heat.
 If you don’t understand the directions or if you are involved in the accident inform the teacher immediately.
 Scientific method steps
o Ask a question (problem)
o Make a hypothesis
o Design and conduct an experiment changing only one variable
o Collect data by using 5 senses
o Analyze the data (charts and graphs)
o Draw conclusion
 Experiment must be conducted at least 3 times. The more time the experiment is conducted the more reliable
your data and conclusion is.
 3 types of variables:
o Independent variable: variable that the scientist purposely changes in an experiment.
o Dependent variable: variable that is observed or measured in an experiment.
o Control variable: variable that remains the same in the experiment.
 In order to get valid (true) conclusion, a scientist must change only one variable.
Humans in Space:
 There are at least 4 reasons why life exist on earth and they are:
o Earth has water
o Earth has breathable atmosphere (78% nitrogen, 21% oxygen, 1% other gases)
o Earth has suitable climate
o Earth’s distance from the sun is just right
 When astronauts travel outside the international space station they need a space suit so they can breathe.
Cell theory states:
 All living things are made of cells.
 Cells are the basic unit of structure and function in living things.
 Cells come from other cells.
Cell structure and functions:
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Eukaryotic cell has a membrane bound nucleus in which genetic material is found. Example: plant and animal
cell.
Prokaryotic cell does not have a membrane bound nucleus as their genetic material floats in the cell. The
example of prokaryotic cell would be bacteria.
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Animal cells do not have chloroplast and cell wall.
Structure
Cell membrane
Cell Wall
Nucleus
Cytoplasm
Function
Allow substances such as water to move into the cell and waste such as carbon
dioxide to move out of the cell.
Gives the plant cell structure, support, protection, and keeps the tree tall and
firm.
It controls what occur in the cell. It holds the genetic material (gene, DNA,
chromosome).
Gel-like structure that holds the organelles in place. The area between the
nucleus and the cell membrane.
It stores food, water and waste in the cell. A plant cell has a large central vacuole
while animal cells have many small vacuoles.
Structure that makes energy for the cell. It uses glucose and oxygen to make ATP
for the cell. Cellular respiration occurs in the mitochondria.
Green structure in the plant cells that captures sunlight to make glucose (sugar).
Energy is transformed from radiant to chemical in the chloroplast.
Photosynthesis occurs in the chloroplast.
Vacuole
Mitochondria
Chloroplast
Cell organization:
Cells  tissues  organs  organ system  organism
Muscle cells  Muscle tissue  Tongue, esophagus, stomach  digestive system  human
Photosynthesis:
 Photosynthesis is the process by which plants make their own food.
 Plants take in carbon dioxide, water, and sunlight to make glucose and oxygen.
 Photosynthesis occurs in chloroplast.
 Animal cells don’t have chloroplast because they don’t make their own food. They have to eat other
organisms to get glucose in their body.
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Photosynthesis changes radiant energy from the sun to chemical energy in glucose.
Cellular respiration is the process by which cells make energy.
The process of making energy occurs in the mitochondria.
Glucose in presence of oxygen is broken down to create ATP (energy), water, and carbon dioxide.
Carbon dioxide is the waste product that is eliminated from our body through exhalation (breathing out).
Tropism: Plants response to the stimulus either towards or away from the stimuli.
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Positive response: It goes towards the stimulus
Negative response: It goes away from the stimulus
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4 types of external stimuli that plants response to:
 Phototropism (light)
o The shoots (leaves and stem) respond positively growing towards the
light and roots responds negatively by going away from the light.
 Thigmotropism (touch)
o When the vines curl around the support it responds positively.
 Geotropism or Gravitotropism (Earth or gravity)
o The roots respond positively and shoot responds negatively.
 Hydrotropism (water)
o The roots respond positively and shoot responds negatively.
Organic compounds:
 Elements are the smallest substance that cannot be broken down.
 Compounds are made of two or more elements that are chemically combined.
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Organic compounds are compounds that contain the element Carbon.
Inorganic compounds are compounds that do not contain the element Carbon.
Heredity and genetic material:
 Heredity is the passing of genetic material from parents to offspring.
 Trait is physical or non-physical characteristics that one has (example: brown eyes, quiet, etc.)
 You get genetic materials not only from your parents, but also from your grandparents.
 Gene is the segment of DNA that gives you a certain traits
 Inherited traits are passed down from parent through offspring through genetic material.
 Acquired traits are traits you get from the environment and are not passed from parent through
offspring through genes such as hair color, hair type, making muscles, etc.
 Chromosomes are threadlike structure which is made of proteins and DNA found in the nucleus of
eukaryotic cell.
 Genetic material from small to large: Gene -> DNA -> Chromosome. The genetic material is found in
the nucleus of the plant and animal cell.
Reproduction
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Sexual reproduction involves 2 parents and the offsprings are genetically diverse from the parents.
Diverse means different.
Sperm is the male sex cell.
Egg is the female sex cell.
Asexual reproduction involves 1 parent and the offsprings are genetically uniform to the parents.
Uniform means exactly (100%) the same.
Sexual reproduction
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Involves 2 parents
Offsprings (children) are genetically diverse from
both parents.
Involves exchanging of genetic materials in the
offspring.
Offsprings don’t look exactly like parents, but look
similar to the parents.
Offsprings receive traits from both parents
Species can adapt to a new environment
conditions.
It is slower, requires energy, and time to look for
mates
Increases the species chance of survival
Asexual reproduction
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Involves 1 parent
Offsprings are genetically uniform to the parent
Parents pass down 100% of genes to the offspring
Faster and takes less energy.
Need less care.
Biodiversity and sustainability:
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Biodiversity is the variety of species, genetic material, and ecosystems found on the Earth.
The ability of an ecosystem to remain same despite changing conditions is called its
sustainability.
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Diversity within a species increases the chances that the species will survive as there are many
options available for the organisms to eat. If one organism dies in a food web, a predator can
eat other organism. The ecosystem will remain the same in the biodiverse ecosystem despite
any change or disturbance. In addition to, biodiverse ecosystem preserves the resources that
are valuable to us and keeps the conditions of the planet suitable for humans to live.
Natural Selection and Selective breeding:
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Natural selection: Natural selection is the process by which organisms that inherit helpful traits tend to
reproduce more successfully than other organisms do.
Adaptation: An inherited trait that improves survival and reproductive success of an organism is an adaptation.
Natural selection and adaptation are based upon inherited traits which mean you are born with the traits and
you cannot change the trait to be selected to survive and reproduce.
Selective breeding or artificial selection is the process of selecting and breeding organisms that have certain
desired traits. Example: different dog breeds.
Evolution through natural selection is the process in which organisms change over time through natural
selection. Here are the 4 steps of evolution through natural selection.
a. There is variation in traits. For example, some beetles are green and some are brown.
b. There is differential reproduction. Since the environment can't support unlimited population growth, not
all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by
birds and survive to reproduce less often than brown beetles do.
c. There is heredity. The surviving brown beetles have brown baby beetles because this trait has a genetic
basis.
d. End result. The more advantageous trait, brown coloration, which allows the beetle to have more offspring,
becomes more common in the population. If this process continues, eventually, all individuals in the
population will be brown.
Dichotomous keys: A dichotomous key is a tool that allows the user to determine the identity of items in the
natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. Keys consist of a series of
choices that lead the user to the correct name of a given item.
Here are the 5 short essay questions that are on the final exam.
1. Describe the 3 characteristics needed for life to exist on another planet.
2. Draw a Venn diagram comparing plant and animal cells
3. Compare and contrast sexual and asexual reproduction.
4. Explain how biodiversity and sustainability are related.
5. Describe natural selection through an example.