GED Science Preparation Course: Life science: the human body, health and cells

1. Pergunta 1 de 17

   Which list shows the levels of organization from smallest to largest?

   • AOrgan, tissue, cell, organ system, organism
   • BCell, organ, tissue, organism, organ system
   • CTissue, cell, organ, organism, organ system
   • DCell, tissue, organ, organ system, organism
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   Resposta: D. Cell, tissue, organ, organ system, organism

   Cells form tissues, tissues form organs, organs form organ systems, and organ systems make up the organism.

2. Pergunta 2 de 17

   Which cell part holds the DNA and controls the cell?

   • ACell membrane
   • BMitochondrion
   • CRibosome
   • DNucleus
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   Resposta: D. Nucleus

   The nucleus holds the cell's DNA and directs its activities.

3. Pergunta 3 de 17

   Which cell part releases energy from food through cellular respiration?

   • ACell wall
   • BNucleus
   • CChloroplasts
   • DMitochondria
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   Resposta: D. Mitochondria

   Mitochondria carry out cellular respiration, releasing energy from glucose.

4. Pergunta 4 de 17

   A scientist sees a cell with a cell wall and chloroplasts. What kind of cell is it most likely from?

   • AA plant
   • BA human
   • CA mosquito
   • DA dog
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   Resposta: A. A plant

   Cell walls and chloroplasts are found in plant cells but not in animal cells such as those of dogs, humans and mosquitoes.

5. Pergunta 5 de 17

   Which statement is part of cell theory?

   • AOnly animals are made of cells
   • BCells form from nonliving matter every day
   • CNew cells come from existing cells
   • DOrgans are the basic unit of life
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   Resposta: C. New cells come from existing cells

   Cell theory says all living things are made of cells, the cell is the basic unit of life, and new cells come from existing cells.

6. Pergunta 6 de 17

   What does mitosis produce?

   • AOne cell with double the DNA
   • BSex cells with half the chromosomes
   • CTwo identical cells
   • DEggs and sperm only
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   Resposta: C. Two identical cells

   Mitosis makes two identical cells for growth and repair. Meiosis makes sex cells with half the chromosome number.

7. Pergunta 7 de 17

   A human body cell has 46 chromosomes. How many chromosomes does a human egg cell have?

   • A92
   • B46
   • C12
   • D23
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   Resposta: D. 23

   Meiosis halves the chromosome number, so sex cells have 46 ÷ 2 = 23 chromosomes.

8. Pergunta 8 de 17

   During a run, your heart beats faster and you breathe faster. Why?

   • AYour bones need extra blood flow so they can grow during exercise
   • BYour kidneys must filter extra oxygen out of the blood
   • CMuscles need more oxygen, so the heart and lungs work harder
   • DYour digestive system must absorb food faster during a run
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   Resposta: C. Muscles need more oxygen, so the heart and lungs work harder

   Body systems work together: the lungs take in more oxygen and the heart moves it faster to the working muscles.

9. Pergunta 9 de 17

   What is homeostasis?

   • APassing traits from parents to their children
   • BKeeping conditions inside the body stable
   • CGrowing new cells by meiosis
   • DBreaking down food in the stomach
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   Resposta: B. Keeping conditions inside the body stable

   Homeostasis keeps internal conditions such as temperature and blood sugar within a steady range.

10. Pergunta 10 de 17

    You start shivering on a very cold day. What is this an example of?

    • ANegative feedback that keeps body temperature stable
    • BA chemical change in the skin caused by the cold air
    • CAn infection caused by a virus that lives in cold places
    • DPositive feedback that cools the body further
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    Resposta: A. Negative feedback that keeps body temperature stable

    In negative feedback, a change triggers a response that reverses it. Shivering makes heat when the body gets too cold.

11. Pergunta 11 de 17

    After a meal, blood sugar rises. Which hormone brings it back down?

    • AInsulin
    • BGlucose
    • CHemoglobin
    • DOxygen
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    Resposta: A. Insulin

    The pancreas releases insulin, which lowers blood sugar. This is part of homeostasis.

12. Pergunta 12 de 17

    Which nutrient is the body's main source of energy?

    • ACarbohydrates
    • BMinerals
    • CWater
    • DVitamins
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    Resposta: A. Carbohydrates

    Carbohydrates are the main energy source. Vitamins, minerals and water do not supply Calories.

13. Pergunta 13 de 17

    A snack has 12 grams of fat. Fat gives 9 Calories per gram. How many Calories come from fat?

    • A21 Calories
    • B48 Calories
    • C108 Calories
    • D120 Calories
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    Resposta: C. 108 Calories

    12 g × 9 Calories per gram = 108 Calories. 48 would use 4 Calories per gram, which is for carbohydrate and protein.

14. Pergunta 14 de 17

    Jordan's daily energy is shown in the table. If this continues, what is most likely to happen?

    	Calories per day
    Calories eaten	2,500
    Calories used	2,200

    • AJordan's weight cannot change because Calories are used up by digestion
    • BJordan uses stored fat to make up a 300-Calorie shortfall
    • CJordan loses weight because the body burns the extra 300 Calories off as heat
    • DJordan stores the extra 300 Calories a day, mostly as fat, and gains weight
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    Resposta: D. Jordan stores the extra 300 Calories a day, mostly as fat, and gains weight

    Jordan takes in 2,500 − 2,200 = 300 more Calories than he uses each day. The body stores extra energy, mostly as fat.

15. Pergunta 15 de 17

    How does a vaccine help prevent disease?

    • AIt kills all of the bacteria that live in the body, good and bad
    • BIt replaces old red blood cells with new ones
    • CIt trains the immune system to recognize a pathogen
    • DIt cures diseases that are caused by genes
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    Resposta: C. It trains the immune system to recognize a pathogen

    A vaccine prepares the immune system so it can respond quickly to the real pathogen.

16. Pergunta 16 de 17

    A doctor says a patient's illness is caused by a virus. Why would an antibiotic not help?

    • AAntibiotics only work on fungi
    • BViruses are too large for antibiotics
    • CAntibiotics kill bacteria but do not work on viruses
    • DAntibiotics only prevent disease spread by mosquitoes
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    Resposta: C. Antibiotics kill bacteria but do not work on viruses

    Antibiotics act on bacteria. They have no effect on viruses.

17. Pergunta 17 de 17

    Malaria spreads when mosquitoes bite people. In this case, what is the mosquito called?

    • AA vector
    • BA decomposer
    • CA producer
    • DA vaccine
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    Resposta: A. A vector

    A vector is a living thing, such as a mosquito, that carries a pathogen from one host to another.

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