Cell Organelles and Functions Quiz
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Questions and Answers

What is the primary function of centrioles in animal cells?

  • Organizing microtubules for spindle fiber formation (correct)
  • Producing ATP molecules
  • Synthesis of ribosomal RNA
  • Contracting muscle fibers

    • Which structure is responsible for controlling the exchange of materials between the nucleus and cytoplasm?

  • Centrosome
  • Rough endoplasmic reticulum
  • Nuclear pores (correct)
  • Cristae

    • What type of cells contain centrioles?

  • Both plant and animal cells
  • Neither plant nor animal cells
  • Animal cells only (correct)
  • Plant cells only

    • Which component within the nucleus is directly responsible for ribosomal RNA synthesis?

    <p>Nucleolus</p> Signup and view all the answers

    What is the shape of the chloroplasts found in plant cells?

    <p>Biconvex</p> Signup and view all the answers

    During what phase of the cell cycle do centrioles replicate?

    <p>Interphase</p> Signup and view all the answers

    What is the main role of the nuclear DNA?

    <p>Carrying genetic instructions for protein synthesis</p> Signup and view all the answers

    Which of the following organelles is NOT found in plant cells?

    <p>Centrioles</p> Signup and view all the answers

    What process occurs in the Golgi apparatus that involves the addition of carbohydrates to proteins?

    <p>Glycosylation</p> Signup and view all the answers

    Which of the following correctly describes the function of lysosomes?

    <p>Digestion of excess or worn-out organelles</p> Signup and view all the answers

    How are the enzymes in lysosomes synthesized and transported?

    <p>Synthesized on the rough endoplasmic reticulum and transported to the Golgi body</p> Signup and view all the answers

    What role does the cristae in mitochondria serve?

    <p>Increase surface area for ATP synthesis</p> Signup and view all the answers

    What is the primary role of the Golgi apparatus?

    <p>Package and transport proteins and lipids</p> Signup and view all the answers

    What is the structure of mitochondria characterized by?

    <p>Rod shape with double membrane bound</p> Signup and view all the answers

    Which structural feature distinguishes mitochondria from bacteria?

    <p>Presence of cristae</p> Signup and view all the answers

    What type of DNA is found in prokaryotic cells?

    <p>Circular and naked</p> Signup and view all the answers

    Which statement about the Golgi apparatus is false?

    <p>It synthesizes hydrolytic enzymes directly.</p> Signup and view all the answers

    Which of the following organelles can only be observed using an electron microscope?

    <p>Lysosomes</p> Signup and view all the answers

    What is primarily found in the matrix of mitochondria?

    <p>Circular DNA and ribosomes</p> Signup and view all the answers

    Which component is found in eukaryotic cells but not in prokaryotic cells?

    <p>Golgi body</p> Signup and view all the answers

    What is the primary function of the slime capsule in prokaryotic cells?

    <p>To protect against dehydration and immune response</p> Signup and view all the answers

    How does the average size of prokaryotic cells compare to that of eukaryotic cells?

    <p>Prokaryotic cells are smaller, averaging 0.5-5 micrometers</p> Signup and view all the answers

    What type of ribosomes do prokaryotic cells primarily contain?

    <p>70S ribosomes</p> Signup and view all the answers

    Which feature is shared by both mitochondria and chloroplasts?

    <p>Double membrane structure</p> Signup and view all the answers

    What is the main purpose of using centrifugation in cell fractionation?

    <p>To separate cell structures based on their relative density</p> Signup and view all the answers

    Which organelle is primarily responsible for protein synthesis and localization in cells?

    <p>Ribosomes</p> Signup and view all the answers

    Which of the following is NOT a membranous organelle?

    <p>Ribosome</p> Signup and view all the answers

    What is the primary function of the thylakoids in chloroplasts?

    <p>Site of light-dependent reactions in photosynthesis</p> Signup and view all the answers

    What characterizes membranous organelles in a cell?

    <p>They contain enzymes that can function in an isolated environment</p> Signup and view all the answers

    Which component of the chloroplast is responsible for the site of light-independent reactions?

    <p>Stroma</p> Signup and view all the answers

    Which statement accurately describes the structure of a large permanent vacuole?

    <p>Occupies 80% of the total plant cell volume</p> Signup and view all the answers

    Which organelle is involved in the synthesis of ATP and is often referred to as the powerhouse of the cell?

    <p>Mitochondria</p> Signup and view all the answers

    What is a function of plasmodesmata in plant cells?

    <p>Facilitates communication and transport between cells</p> Signup and view all the answers

    Which process is used to track the pathway of secreted proteins in a cell?

    <p>Use of radioactively labelled amino acids</p> Signup and view all the answers

    What structure connects the endoplasmic reticulum to the nuclear envelope?

    <p>Membrane</p> Signup and view all the answers

    What is the role of the tonoplast in a large permanent vacuole?

    <p>Regulates exchange of substances via osmosis</p> Signup and view all the answers

    What is the primary characteristic of amyloplasts?

    <p>They store starch in a colorless form</p> Signup and view all the answers

    What differentiates non-membranous organelles from membranous ones?

    <p>Non-membranous organelles do not have a surrounding membrane</p> Signup and view all the answers

    Which organelle is primarily associated with the endosymbiont theory?

    <p>Chloroplast</p> Signup and view all the answers

    Which of the following is NOT a characteristic of both chloroplasts and mitochondria?

    <p>They both carry out photosynthesis</p> Signup and view all the answers

    What is the primary function of the Rough Endoplasmic Reticulum (RER)?

    <p>Protein synthesis and modification</p> Signup and view all the answers

    Where are 70S ribosomes typically found?

    <p>In prokaryotic cells and mitochondria</p> Signup and view all the answers

    What characterizes the Smooth Endoplasmic Reticulum (SER)?

    <p>It is involved in the synthesis of lipids and steroid hormones.</p> Signup and view all the answers

    What do small sacs bud off from the Rough Endoplasmic Reticulum form?

    <p>Golgi bodies</p> Signup and view all the answers

    Which of the following describes the Golgi apparatus?

    <p>A stack of flattened membrane-bound sacs with no interconnecting membranes</p> Signup and view all the answers

    Which type of ribosome is primarily associated with the synthesis of proteins for intracellular use?

    <p>Free ribosomes in the cytoplasm</p> Signup and view all the answers

    Which of the following is true about the differences in ribosomal types?

    <p>80S ribosomes are associated with eukaryotes.</p> Signup and view all the answers

    What is the function of polypeptide chains that enter the cisternal space of the Rough Endoplasmic Reticulum?

    <p>They undergo folding and modification.</p> Signup and view all the answers

    Study Notes

    Cell Organelles and Their Functions

    • Cell fractionation uses centrifugation to separate cell structures based on their density. Higher centrifuge speeds allow for better separation of smaller particles.
    • Radioactive labelling of chemical substances within cells helps researchers pinpoint their location within the cell. An example is using radioactively labelled amino acids to track protein synthesis.
    • Ribosomes, the rough endoplasmic reticulum, the Golgi apparatus, and the plasma membrane participate in protein synthesis. Ribosomes produce proteins, the rough ER modifies those proteins, and the Golgi apparatus packages the proteins for transport.
    • The labelled protein's path, from ribosomes to rough endoplasmic reticulum to the Golgi apparatus to the plasma membrane, is tracked using microscopy or electrophoresis.

    Cell Structure and Organelles

    • Cell structures are divided into two groups:
      • Membranous organelles: These organelles, enclosed by membranes, maintain optimal pH and specialized functions within the cell. Examples include mitochondria for respiration, chloroplasts for photosynthesis, and lysosomes with hydrolytic enzymes.
      • Non-membranous organelles: Ribosomes, starch grains, and centrosomes are examples of non-membranous organelles.

    Endoplasmic Reticulum

    • The endoplasmic reticulum (ER) is a network of membranes that extends throughout the cytoplasm. It connects to the nuclear envelope.
    • The ER exists as two types (with distinct functions):
      • Rough ER: Studded with ribosomes and involved in protein synthesis and modification. Proteins made travel through the sacs of the ER, and are often folded into their final form. The rough ER is also responsible for transporting the proteins.
      • Smooth ER: Lacks ribosomes and involved in lipid synthesis and detoxification. Some cells, like liver cells, have a lot of smooth ER involved in detoxification.

    Ribosomes

    • Ribosomes are the site of protein synthesis within cells.
    • They are composed of two subunits, large and small, each made from ribosomal RNA and protein.
    • Ribosomes can be free-floating in the cytoplasm, or bound to the endoplasmic reticulum. The attached ones synthesize proteins meant for secretion or insertion into membranes.

    Golgi Apparatus

    • The Golgi apparatus is a stack of flattened sacs involved in processing and packaging proteins and lipids that are produced in the cell and destined for secretion.
    • It collects proteins from the ER in vesicles, modifies them chemically, and packages them into secretory vesicles for transport to destinations within or outside the cell. Carbohydrates can also be added or modified.

    Lysosomes

    • Lysosomes are membrane-bound organelles containing hydrolytic enzymes.
    • They are involved in digesting cellular waste, foreign materials, or damaged organelles/parts of the cell.

    Mitochondria

    • Mitochondria are double-membrane organelles containing their own DNA.
    • They are responsible for aerobic respiration, producing ATP, the cell's primary energy currency.
    • The folded inner membrane (cristae) increases surface area allowing more respiration to happen.
    • They contain their own DNA and ribosomes. They are self-replicating.

    Nucleus

    • The nucleus is the largest organelle in a eukaryotic cell.
    • It's a double-membraned organelle with a nuclear envelope containing pores that allow material to pass between the nucleus and the cytoplasm.
    • The nucleus contains the cell's DNA organized as chromatin, is the site of ribosome synthesis in the nucleolus.

    Chloroplasts

    • Chloroplasts are double-membrane organelles found in plant cells and some other organisms. These organelles contain their own DNA and are where photosynthesis occurs.
    • They have an internal system of membranes that includes thylakoids and grana (stacks of thylakoids), where light-dependent reactions take place.
    • The stroma is the fluid-filled space surrounding the thylakoids and grana where the light-independent reactions of photosynthesis occur.

    Large Vacuole

    • Large vacuoles are fluid-filled sacs that take up a large portion of the interior of a plant cell.
    • They maintain turgor pressure in the cell and are involved in storage of water, nutrients, ions, and waste products..
    • The membrane that surrounds the vacuole, the tonoplast, manages transport of molecules into and out of the vacuole.

    Plasmodesmata

    • Plasmodesmata are channels in plant cell walls that connect the cytoplasm of neighboring cells.
    • They allow for communication and exchange of small molecules between the cells.

    Amyloplasts

    • Amyloplasts are double-membrane-bound organelles specializing in starch storage.
    • They are found in many plant cells, particularly those with substantial starch deposits (such as potato tubers).

    Prokaryotic vs. Eukaryotic Cells

    • Prokaryotic cells (like bacteria) lack a nucleus and other membrane-bound organelles. Their DNA is circular and located in the cytoplasm.
    • Eukaryotic cells (like animal and plant cells) have a nucleus and other membrane-bound organelles. Their DNA is linear and contained within the nucleus.

    Cell Walls

    • Plant cells, fungi, and some bacteria have cell walls, rigid structures that provide support and protection.
    • Animal cells lack cell walls.
    • Bacterial cell walls are made of peptidoglycan (murein), plant cell walls from cellulose.

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    Cell Organelles - 7-20 PDF

    Description

    Test your knowledge on cell organelles and their roles in protein synthesis and cellular functions. This quiz covers cell fractionation, radioactive labeling, and the journey of proteins within the cell. Prepare to explore the intricate workings of cell structures and their importance.

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