Study Guide Science Grade 7
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or statement true.
1. Viruses are considered to be nonliving because they are not made of protein.
2. The inner core of a virus contains genetic material.
____ 3. When a virus invades a living cell, its outer coat takes over the cell’s functions.
____ 4. Unlike the cells of other organisms, the cells of bacteria do not have nuclei.
____ 5. The cell membrane is the outermost structure of most bacterial cells.
____ 6. Bacteria that are decomposers break down large chemicals in dead organisms into small chemicals.
____ 7. Scientists think that today’s eubacteria closely resemble Earth’s first life forms.
____ 8. Binary fission occurs when a bacterium transfers some of its genetic material to another bacterium.
____ 9. The bacteria that cause Lyme disease are transmitted through tick bites.
____ 10. Vaccines such as penicillin are chemicals that can kill bacteria.
Complete each sentence or statement.
11. A virus can multiply only when it is inside a(n) ____________________.
12. Although viruses are nonliving they act like ____________________ because they destroy the cells in which they multiply.
13. A virus’s ____________________ contains the instructions for making new viruses.
14. The shape of the ____________________ in a virus’s coat allows the virus to attach to certain cells.
15. A virus that begins to multiply immediately after it enters a cell is called a(n) ____________________ virus.
16. When a(n) ____________________ virus enters a cell, the virus’s genetic material becomes part of the cell’s genetic material
17. Some bacteria move by using a long, whiplike structure called a(n) ____________________.
18. Bacteria are called ____________________ because their genetic material is not contained in nuclei.
19. Bacterial cells contain structures called ____________________, which are chemical factories where proteins are produced.
20. Many bacteria are called ____________________ because they break down large chemicals in dead organisms into small chemicals.
21. Bacteria in swellings on the roots of peanut plants convert ____________________ gas from the air into compounds the plants need to grow.
22. Many bacteria in the ____________________ kingdom live in extreme environments, such as hot springs.
23. When bacteria reproduce by ____________________, one cell divides to form two identical cells.
24. During a process called ____________________, one bacterium divides to form two identical bacteria.
25. Illnesses that pass from one organism to another are called ____________________.
26. Infectious diseases are spread by contact with contaminated people and objects, with animals, and with ___________________
27. Some bacteria cause diseases by producing poisons known as __________________
28. A ____________________ is a substance that stimulates the body to produce chemicals that destroy viruses or bacteria.
29. The ability to ____________________ is the only characteristic that viruses share with living organisms.
30. Bacteria that survive in the presence of an antibiotic are said to be ____________________ to the antibiotic.
Study Guide Science Grade 7
1. F, cells 2. T 3. F, genetic material 4. T 5. F, cell wall 6. T 7. F, archaebacteria 8. F, conjugation 9. T 10. F, antibiotics 12. parasites 13. genetic material 14. proteins 15. active 16. hidden 17. flagellum 18. prokaryotes 19. ribosomes 20. decomposers 21. nitrogen 22. archaebacteria 23. binary fission 24. binary fission 25. infectious diseases 26. environmental sources 27. toxins 28. vaccine 29. multiply 30. resistant