Module 4 Part 2: Plant and animal cell structures

Vocabulary

Cell wall

A rigid protective structure outside certain cells.

Plasmodesmata

Small pores in plant cell walls that allow substances to pass through.

Middle lamella

A thin film, mainly pectin, between neighboring plant cell walls.

Nucleus

The organelle that holds the cell’s main DNA and acts as its control center.

Nuclear membrane

A porous membrane separating the nucleus from the cytoplasm.

Chromatin

Strands of DNA and proteins, or RNA and proteins, in the nucleus, as described on these pages.

Nucleolus

The region inside the nucleus where RNA is made and ribosomes are assembled.

Endoplasmic reticulum

A network of folded membranes that helps transport materials and performs other cell tasks.

Rough ER

ER dotted with ribosomes that receives and can modify newly made proteins.

Smooth ER

ER without ribosomes that makes lipids and other chemicals and inactivates certain toxic wastes.

Golgi apparatus

Organelles that sort, store, modify, and package proteins and lipids.

Vacuole

A larger membrane-bound sac used to store food, water, or waste.

Vesicle

A smaller membrane-bound sac used mainly to transport materials.

Turgor pressure

Pressure inside plant cells caused by water-filled central vacuoles that helps keep plants rigid.

Lysosome

An animal-cell organelle containing enzymes that break down molecules and worn-out cell parts.

Peroxisome

An organelle containing enzymes that break down fatty acids and hydrogen peroxide.

Mitochondria

Double-membrane organelles responsible for respiration and supplying energy.

Plastids

Double-membrane organelles in plants, algae, and some protozoa that make or store food.

Chloroplasts

Plastids containing green chlorophyll used in photosynthesis.

Leucoplasts

Nonpigmented plastids that store starches or oils.

Cytoskeleton

A network of protein fibers that supports cell shape, positions organelles, and helps movement.

Microfilaments

Fine, threadlike proteins involved in cell support, contraction, and movement.

Intermediate filaments

Supporting protein fibers roughly twice as thick as microfilaments.

Microtubules

Hollow protein tubes involved in movement, transport, and chromosome separation.

Centrioles

Paired animal-cell organelles that organize fibers needed for cell division.

Practice questions

1. Cell wall protection and materials

   1.What is the main function of a cell wall?

   To assemble ribosomesTo protect the cell from its surroundingsTo store nuclear DNATo package proteins

2. Cell wall protection and materials

   2.The tough carbohydrate fiber typically found in plant cell walls is ____.

   Check

3. Passage through cell walls

   3.How can nutrients pass through a plant cell wall?

   Through small pores called plasmodesmataBy being made inside centriolesThrough the nucleolusBy removing the entire wall

4. Passage through cell walls

   4.The small holes in plant cell walls are called ____.

   Check

5. Plant cell wall layers

   5.Where do secondary cell walls form after a plant cell has matured?

   Outside the middle lamellaInside the original cell wallInside the nucleolusAround each ribosome

6. Plant cell wall layers

   6.After secondary walls form, the original wall is called the ____.

   Check

7. The nucleus stores instructions

   7.Why is the nucleus often called the cell’s control center?

   It stores the cell’s main DNA.It stores all the cell’s water.It forms the outer cell wall.It breaks down hydrogen peroxide.

8. The nucleus stores instructions

   8.DNA stored in the nucleus is called ____ DNA.

   Check

9. The nuclear membrane

   9.Which structure separates the nucleus from the cytoplasm?

   Middle lamellaNuclear membranePrimary cell wallCentral vacuole

10. The nuclear membrane

    10.Materials move between the nucleus and cytoplasm through nuclear ____.

    Check

11. The nucleolus assembles ribosomes

    11.Where are ribosomes assembled before being transported out of the nucleus?

    In the middle lamellaIn the central vacuoleIn the nucleolusIn the cell wall

12. The nucleolus assembles ribosomes

    12.The center inside the nucleus where RNA is made is the ____.

    Check

13. Rough ER processes proteins

    13.What makes rough ER different from smooth ER?

    Rough ER contains chlorophyll.Rough ER has no membranes.Rough ER is outside the cell.Rough ER is dotted with ribosomes.

14. Rough ER processes proteins

    14.New proteins from attached ribosomes enter the ____ ER, where they can be chemically modified.

    Check

15. Smooth ER makes chemicals and handles toxins

    15.Which substance is made in smooth ER?

    ChromatinNuclear DNALipidsCellulose fibers only

16. Smooth ER makes chemicals and handles toxins

    16.Unlike rough ER, smooth ER has no attached ____.

    Check

17. The Golgi is a packaging center

    17.Which organelle acts much like a mailing service by packaging and addressing molecules?

    NucleolusMitochondrionGolgi apparatusCell wall

18. The Golgi is a packaging center

    18.Proteins and lipids are sorted and stored in the ____ until needed.

    Check

19. Vacuoles store and vesicles transport

    19.Which comparison correctly describes vacuoles and vesicles?

    Vacuoles are smaller and more mobile.Vesicles have no membranes.Both are protein fibers.Vacuoles are larger, while vesicles are smaller and more mobile.

20. Vacuoles store and vesicles transport

    20.A smaller membrane-bound sac carrying proteins from the ER to the Golgi apparatus is a ____.

    Check

21. Central vacuoles and turgor pressure

    21.What happens as a plant cell’s central vacuole fills with water?

    It removes the cell wall.It pushes the cytoplasm and organelles against the cell wall.It turns into a nucleus.It destroys all the cell’s proteins.

22. Central vacuoles and turgor pressure

    22.The pressure that helps a well-watered plant stay firm is called ____.

    Check

23. Lysosomes digest and clean up

    23.Which organelle contains enzymes for hydrolysis reactions that break down proteins, carbohydrates, and some lipids?

    ChloroplastLysosomeCentrioleNucleolus

24. Lysosomes digest and clean up

    24.An animal cell’s organelle that acts as a cleaning crew for worn-out cell parts is the ____.

    Check

25. Peroxisomes break down harmful substances

    25.Which organelle breaks down hydrogen peroxide before it can build up and harm the cell?

    Central vacuoleGolgi apparatusNucleolusPeroxisome

26. Peroxisomes break down harmful substances

    26.The enzyme in peroxisomes that breaks down hydrogen peroxide is ____.

    Check

27. Mitochondria supply energy

    27.Why are mitochondria called the powerhouses of the cell?

    They carry out respiration and provide energy.They store all the cell’s food in one sac.They produce the cell wall.They assemble all ribosomes.

28. Mitochondria supply energy

    28.Muscle cells need more energy than skin cells, so they generally contain more ____.

    Check

29. Plastids make or store food

    29.Which group contains chloroplasts, chromoplasts, and leucoplasts?

    LysosomesPlastidsCentriolesVesicles

30. Plastids make or store food

    30.The green pigment found in chloroplasts is ____.

    Check

31. The cytoskeleton supports and organizes

    31.What is the cytoskeleton?

    A single water-storage sacA layer of cellulose outside the cellA network of protein fibersA cluster of photosynthetic pigments

32. The cytoskeleton supports and organizes

    32.The network that helps a cell keep its shape and holds organelles in position is the ____.

    Check

33. Microfilaments help cells contract

    33.Which cytoskeletal fibers are especially important for muscle-cell contraction?

    MicrofilamentsIntermediate filamentsCellulose fibersChromatin strands

34. Microfilaments help cells contract

    34.Fine, threadlike cytoskeletal proteins involved in amoeba movement are called ____.

    Check

35. Intermediate filaments strengthen cells

    35.What is the main role of intermediate filaments?

    Making lipidsStoring waterStrengthening and supporting the cellBreaking down peroxide

36. Intermediate filaments strengthen cells

    36.Skin cells contain many ____ because they need to hold their shape well.

    Check

37. Microtubules provide tracks and movement

    37.Which fibers provide tracks along which organelles and vesicles can travel?

    Cellulose fibersMicrotubulesChromatin strandsIntermediate filaments

38. Microtubules provide tracks and movement

    38.During cell division, ____ help separate chromosomes.

    Check

39. Centrioles organize division fibers

    39.What is the main job of centrioles in animal cells?

    To store starchTo make RNATo organize fibers required for cell divisionTo maintain turgor pressure

40. Centrioles organize division fibers

    40.The region near the nucleus containing the two centrioles in an animal cell is the ____.

    Check

Cumulative review

Questions from earlier parts of Module 4.

1. Review · Module 4 Part 1: Janssen and the first microscope

   1.Who invented the first compound microscope around 1595?

   Hans and Zacharias JanssenRobert HookeRudolf VirchowTheodor Schwann

2. Review · Module 4 Part 1: Janssen and the first microscope

   2.A Dutch father and son built the first compound microscope. About what year was that?

   1595166518331855

3. Review · Module 4 Part 1: Janssen and the first microscope

   3.A compound microscope uses ____ lenses.

   Check

4. Review · Module 4 Part 1: Janssen and the first microscope

   4.The first compound microscope was invented by a father-son team with the last name ____.

   Check

5. Review · Module 4 Part 1: Hooke names the cell

   5.Who coined the term "cells"?

   Robert HookeAntonie van LeeuwenhoekMatthias SchleidenRobert Brown

6. Review · Module 4 Part 1: Hooke names the cell

   6.What was Robert Hooke looking at when he first used the word "cells"?

   Thin slices of corkPond waterBlood cellsCheek cells

7. Review · Module 4 Part 1: Hooke names the cell

   7.Why did Hooke choose the word "cells"?

   The compartments reminded him of a monastery's tiny roomsThey looked like jail cellsThey were full of electricityThey were named after a scientist named Cell

8. Review · Module 4 Part 1: Hooke names the cell

   8.Hooke published his drawings in a book called ____ in 1665.

   Check

9. Review · Module 4 Part 1: Cork is dead tissue

   9.When Hooke looked at cork, what did he actually see?

   The leftover cell walls of dead cellsLiving cells with nucleiBacteriaProtozoa

10. Review · Module 4 Part 1: Cork is dead tissue

    10.Cork comes from the bark of which tree?

    OakMaplePineWillow

11. Review · Module 4 Part 1: Cork is dead tissue

    11.Cork is actually ____ tissue, so Hooke saw cell walls, not living cells.

    Check