7th Grade Life Science Final Study Guide
Section 1: Human Body
1. What is the main function of the respiratory system?
To bring O2 (oxygen) to the lungs and remove CO2 (carbon dioxide) from
the Lungs.
2. What is the main function of the circulatory system?
Carries nutrients from the digestive system and oxygen from the
respiratory system to cells and removes waste, carbon dioxide and water
from cells.
3. What is the main function of the digestive system?
Provides nutrients for cells to use for cellular respiration so we can get
energy.
4. How do the digestive, respiratory and circulatory systems work together to deliver oxygen and nutrients
and remove carbon dioxide from your body?
Digestive = nutrients to cells
Respiratory = oxygen in/CO2 out
Circulatory = transports these items throughout the body
5. What is cellular respiration?
Process by which we get energy to our cells happens in the mitochondria.
6. What are the materials needed for cellular respiration?
Need glucose and oxygen
C6H12O6 (sugar) + O2
7. What are the products released in cellular respiration?
Releases ENERGY, carbon dioxide, and water vapor
ENERGY + CO2 + H2O
8. Explain how chemical and mechanical digestion both occur in the mouth.
Mechanical is when you chew the food and physically break it into
smaller pieces.
Chemical is when the enzymes in saliva begin to break down the chemical
bonds in the carbohydrates into sugars.
9. At which stages in your life do you need to eat the most? Why do you need to eat so much at that point
in your life? Explain.
You eat the most when you are growing, because you need carbohydrates
to give you energy and proteins to build and repair cells.
Section 2: Cells
10. What is a tissue?
A collection of cells that work together for a particular function.
11. What is a cell?
The basic unit of structure or building block of living things.
12. Put these terms in order from smallest to largest: organ, cell, tissue, organ system.
Cell, tissue, organ, organ system
13. What is the function of the mitochondria?
It provides energy for the cell and the body by taking in sugar and
oxygen and releasing carbon dioxide and water vapor.
14. Which type of human cell would have the most mitochondria and why?
Muscle cells have the most mitochondria because they are constantly
contracting and doing work for the body.
15. What is the function of the vacuole?
The vacuole stores water.
16. Why is the vacuole larger in plant cells?
The vacuole in a plant is much larger because a plant cannot move to get
water, it can only get it from rain or people, so plants need to store a large
amount of water.
17. List 3 major differences between animal and plant cells.
1) Plants have chloroplasts (green)
2) Plants have a cell wall for protection.
3) Plants have a large central vacuole to store water.
18. What is the function of the red blood cell? Why is it shaped the way it is?
Red blood cells carry oxygen and carbon dioxide to and from cells and
the lungs. It is shaped like a donut so it can carry the oxygen and CO2.
19. What is the function of the nucleus?
It contains DNA which give instructions to make proteins that make
other chemicals in the body.
20. What is the function of the chloroplasts? What process are chloroplasts responsible for in plants?
Chloroplasts change carbon dioxide into oxygen in the light and they
make sugar in the light. This is where photosynthesis happens in plants.
21. How does a cell’s shape influence their function? Give an example.
A nerve cell is a circle with many branches so it can receive and send
many signals to the body.
Section 3: Genetics:
22. List 3 inherited characteristics.
1) Natural hair and eye color
2) Dimples
3) Tongue rolling
23. List 3 acquired characteristics.
1) Scars
2) Tattoos
3) Reading or writing
24. Define heterozygous and give an example. What is another word for heterozygous?
Heterozygous means two different forms of a trait. Ww for widow’s
peak. Another word is hybrid.
25. Define homozygous and give an example. What is another word for homozygous?
Homozygous means the same form of a trait. ww for straight hairline.
Another word is purebred.
26.
D
d
D
DD
d
Dd
Dd
dd
D = dimples
Dd x
a. What is the probability of a DD?
b. What is the probability of a Dd?
c. What is the probability of a dd?
d = no dimples
Dd
25%
50%
25%
75%
What is the probability of not having dimples? 25%
d. What is the probability of having dimples?
e.
27. In humans, the allele for Widow’s peak is dominant (W) to the allele for a Straight hair line (w). If both
parents have a Widow’s peak, how is it possible that one of their children has a Straight hairline? USE
A PUNNETT SQUARE!!
W
w
Both parents must be heterozygous so they have a “w”.
W
WW Ww
w
Ww
ww
28. Explain the two major differences between sexual and asexual reproduction.
(Hint: How many parents does each require? Which produces a genetically identical offspring?)
1) Sexual reproduction = 2 parents
2) Genetically ½ mom and ½ dad
Asexual reproduction = 1 parent
genetically identical to parent
Section 4: Natural Selection:
29. Define adaptation and give an example.
A trait that helps an organism survive and reproduce offspring.
30. A bear’s environment is becoming colder over time. What would happen to the bear population’s fur
over time? How would this help them survive and reproduce better? Explain!
The bear population’s fur should get longer and fuller, to help it stay
warmer, this will allow the bear to survive and produce more offspring.
31. Explain the adaptation(s) a frog has. How do they help them survive and reproduce?
Frogs are amphibians and can live on land and in the water. They also
have camouflage to help them hide from predators. This allows them to
live long enough to reproduce.
32. During the Industrial Revolution, white birch trees (which have whitish bark) became covered with soot
(black dirt) from factories. The peppered moths live in white birch forests. Most peppered moths were
whitish with small gray spots on their wings. Predict how the entire population of peppered moths
changed during the time of the Industrial Revolution. Explain how that adaptation enabled them to
survive and reproduce better.
Over time any moths with a mutation for dark wing will more likely
survive and produce offspring. After many generations the moths will
have dark wings so they will not be seen and not be eaten.
Section 5: Ecology
33. Define abiotic and give an example.
A nonliving thing in the environment, rocks, water, soil, the sun.
34. Define biotic and give an example.
A living thing in the environment, any plant or animal or human.
35. Define decomposer and give an example.
Breaks down living matter and returns the nutrients to the earth.
36. Define producer and give an example.
It can make its own food, some bacteria and all plants are producers.
37. Define consumer and give an example.
Consumers find and eat food(producers or other consumers) animals.
38. Explain how a decomposer is DIFFERENT than a consumer?
Decomposer break down things that are no longer living to return energy
to the environment, consumers use the energy from what they eat.
39. Define competition and give an example.
When two or more species in an area fight over the use of food or a
habitat.
40. Give an example of a predator and its prey.
Predator = Owl or snake
Prey = mouse or frog
41. Define parasitism and give an example.
Parasitism – 1 species benefits, 1 species is harmed
Ex/ Tick and Human: Tick gets blood, Human gets harmed
42. Give an example of symbiosis and explain it.
Commensalism – 1 species benefits, 1 species doesn’t care (1 thumb up, 1 thumb to
the side) Ex/ Bird in Tree: Bird gets a home, Tree doesn’t care
43. What energy role do food webs/food chains always begin with? Why?
All food webs start with producers, they provide the energy for all other
organism and can make their own food.
44. Define herbivore and give an example.
It is a plant eating organism like a rabbit.
45. Define carnivore and give an example.
It is a meat eating organism like a fox.
46. In a food web/food chain, which organism(s) if removed would cause the death of the entire food
web/food chain? Why?
If I removed one organism from the web the entire food web would be
affected because some organisms wouldn’t have predators and
overpopulate. Ex: If I removed a snake, the mouse population would
increase and the grass population would decrease.
47. Give at least 2 reasons a population of fish in a pond might decrease.
1) If they are eaten by a new predator (guppies)
2) If their food source is gone.
48. Give at least 2 reasons a population of fish in a pond might increase.
1) If a predator is now gone from their habitat.
2) If a new adaptation allows them to eat another food available to them.
49.
Mitochondria
nucleus
chloroplast
Label the 1) mitochondria
2) nucleus
3) chloroplast