Biology Chapter: Cells and Organization
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Questions and Answers

What is the primary function of the cell membrane?

  • Provides shape and protects inner organelles (correct)
  • Production of lipids and proteins
  • Storage of genetic information
  • Site of cellular respiration

Which organelle is known as the 'Power House of The Cell'?

  • Nucleus
  • Golgi apparatus
  • Lysosomes
  • Mitochondria (correct)

What specific function do chloroplasts perform in plant cells?

  • Digestion of waste materials
  • Skeletal framework formation
  • Sites of photosynthesis (correct)
  • Transportation of proteins

What is the role of lysosomes in a cell?

<p>Digestion and waste removal (D)</p> Signup and view all the answers

Which organelle is primarily involved in the detoxification process within a cell?

<p>Endoplasmic Reticulum (A)</p> Signup and view all the answers

What is the main function of the Golgi apparatus?

<p>Involvement in secretion and transportation (D)</p> Signup and view all the answers

What is found in the nucleus of a cell?

<p>Genetic information (D)</p> Signup and view all the answers

Which cell organelle is only found in animal cells?

<p>Centrosomes (B)</p> Signup and view all the answers

What is the main function of peroxisomes in the cell?

<p>Metabolism of lipids (A)</p> Signup and view all the answers

Which type of plastid is responsible for storing starch, proteins, and fats?

<p>Leucoplast (C)</p> Signup and view all the answers

What distinguishes ribosomes from other organelles in terms of structure?

<p>They are not membrane-bound (B)</p> Signup and view all the answers

How do vacuoles contribute to the cell's shape?

<p>By giving shape and rigidity (B)</p> Signup and view all the answers

Which statement accurately explains the difference between plant and animal cells?

<p>Plant cells typically have a cell wall, while animal cells do not. (C)</p> Signup and view all the answers

What is a common feature of all eukaryotic cells?

<p>Presence of a plasma membrane (B)</p> Signup and view all the answers

Which type of plastid is known for its green color and role in photosynthesis?

<p>Chloroplast (A)</p> Signup and view all the answers

What role do plants primarily play in an ecosystem?

<p>Producers (D)</p> Signup and view all the answers

What does the fluid mosaic model describe?

<p>The composition and behavior of plasma membranes (A)</p> Signup and view all the answers

What is primarily contained within the cytoplasm?

<p>A jelly-like substance with organelles (D)</p> Signup and view all the answers

Which structure is responsible for synthesizing proteins and RNA within the nucleus?

<p>Nucleoli (C)</p> Signup and view all the answers

What is the primary function of the nucleus in a cell?

<p>Controlling cellular activities and storing DNA (B)</p> Signup and view all the answers

Which of the following describes the Endoplasmic Reticulum's role in a cell?

<p>It serves as the transport system throughout the cell. (C)</p> Signup and view all the answers

What is contained within the nucleus that is responsible for the inheritance of traits?

<p>Chromosomes (A)</p> Signup and view all the answers

What do genes primarily control within an organism?

<p>Inheritance of traits (D)</p> Signup and view all the answers

What characteristic of the nucleus allows it to separate the cytoplasm from the nucleoplasm?

<p>Nuclear membrane (A)</p> Signup and view all the answers

What is the primary function of ribosomes in cells?

<p>Protein synthesis (B)</p> Signup and view all the answers

Which type of plastid is known for storing oils and fats?

<p>Elaioplast (A)</p> Signup and view all the answers

What is the main structural feature of the Golgi apparatus?

<p>Flattened, stacked pouches (B)</p> Signup and view all the answers

What are the two primary components that make up ribosomes?

<p>Ribosomal RNA and ribosomal proteins (C)</p> Signup and view all the answers

What did van Leeuwenhoek first discover in the 1670s?

<p>Bacteria and protozoa (A)</p> Signup and view all the answers

Which type of ribosomes are typically found in eukaryotic cells?

<p>80S (A)</p> Signup and view all the answers

Which scientists are credited with proposing the unified cell theory in the late 1830s?

<p>Matthias Schleiden and Theodor Schwann (A)</p> Signup and view all the answers

What are microbodies primarily characterized by?

<p>Minute size and membrane-bound structure (C)</p> Signup and view all the answers

What role do chromoplasts serve in plants?

<p>Providing characteristic colors to plants (C)</p> Signup and view all the answers

Which statement is NOT part of the modern cell theory?

<p>Cells arise from spontaneous generation (D)</p> Signup and view all the answers

Which aspect of cell theory did Rudolf Virchow famously contribute to?

<p>All cells arise from pre-existing cells (C)</p> Signup and view all the answers

What is a key characteristic of the cytoskeleton in eukaryotic cells?

<p>It is a continuous network of filamentous proteins (C)</p> Signup and view all the answers

What is a common misconception about cell origination proposed by early scientists?

<p>Cells originated through spontaneous generation (D)</p> Signup and view all the answers

Which of the following is considered a fundamental unit of life according to the modern cell theory?

<p>Cells (A)</p> Signup and view all the answers

Which of the following statements regarding cellular composition is true?

<p>Cells carry genetic material passed to daughter cells (B)</p> Signup and view all the answers

Which is true about energy flow in cells?

<p>It is an aspect of metabolism and biochemistry (C)</p> Signup and view all the answers

What shape do plant cells typically have?

<p>Square or rectangular (B)</p> Signup and view all the answers

Which organelle is absent in animal cells but present in plant cells?

<p>Chloroplasts (C)</p> Signup and view all the answers

Where is the nucleus typically located in a plant cell?

<p>On one side of the cell (B)</p> Signup and view all the answers

What is the primary mode of nutrition for plant cells?

<p>Autotrophic (C)</p> Signup and view all the answers

What feature distinguishes the presence of lysosomes in animal cells compared to plant cells?

<p>Lysosomes are present but rare in plant cells (B)</p> Signup and view all the answers

How do the sizes of typical plant and animal cells compare?

<p>Plant cells can be larger than animal cells (B)</p> Signup and view all the answers

Which organelles are present in both plant and animal cells?

<p>Endoplasmic reticulum, Golgi apparatus, mitochondria (C)</p> Signup and view all the answers

What is a function characteristic of centrosomes unique to animal cells?

<p>Cell division and organization (D)</p> Signup and view all the answers

Flashcards

Cell Theory

The cell theory states that all living things are composed of one or more cells, the cell is the basic unit of life, and new cells arise from existing cells.

Unified Cell Theory

Proposed by Matthias Schleiden and Theodor Schwann, this theory initially suggested that cells arose through spontaneous generation, where non-living matter could give rise to life. However, this idea was later disproven.

Virchow's Contribution to Cell Theory

States that "all cells only arise from pre-existing cells." This theory clarified the origin of cells and disproved the earlier idea of spontaneous generation.

Spontaneous Generation (Abiogenesis)

The idea that non-living matter can give rise to life. This theory has been scientifically disproven.

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Cell

The fundamental unit of life, responsible for all structure and function in living things.

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Cellular Division

The process by which cells divide to create new cells.

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Heredity in Cells

Cells contain genetic material (DNA) which is passed on to daughter cells during cellular division. This ensures that the characteristics of the parent cell are inherited.

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Chemical Composition of Cells

All cells from similar species share essentially the same chemical composition. This highlights the fundamental unity of life.

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Fluid Mosaic Model

A model that describes the plasma membrane as a fluid structure with embedded proteins. The membrane is composed of a phospholipid bilayer, which creates a flexible barrier.

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Cytoplasm

The jelly-like substance found within the cell membrane and surrounds the nucleus. It's mainly composed of water, organic, and inorganic compounds. It facilitates many cell processes.

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Nucleus

The control center of the eukaryotic cell. It contains the cell's DNA and is responsible for regulating cellular activity.

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Endoplasmic Reticulum (ER)

A network of membranes that transport materials throughout the cell. It's involved in synthesizing proteins and lipids.

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What is the nucleus?

A double membrane bound organelle found in eukaryotic cells. It is the largest organelle, and it functions as the control center of the cellular activities and is the storehouse of the cell's DNA.

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Nucleoli

They are tiny spherical bodies found within the nucleus. They carry out protein and RNA synthesis.

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Chromosomes

They are thin thread-like structures, located inside the nucleus. They are the carriers of genes.

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Genes

They are a hereditary unit found in organisms. They help with the inheritance of traits from parents to offspring.

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Stroma of Chloroplasts

The fluid-filled space within chloroplasts, containing enzymes for carbohydrate and protein synthesis, 70S ribosomes, and a circular DNA molecule.

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Chromoplasts

Pigment-containing plastids responsible for giving fruits and flowers their vibrant colours (yellow, orange, red) due to carotenoid pigments like xanthophylls and carotene.

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Leucoplasts

Colorless plastids that serve as storage compartments for various nutrients in plants.

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Amyloplast

A type of leucoplast specialized in storing carbohydrates, primarily starch, as seen in potatoes.

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Aleuronplast

A type of leucoplast specialized in storing proteins, like in seeds.

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Elaioplast

A type of leucoplast specialized in storing oils and fats, primarily in seeds.

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Ribosomes

Small, non-membrane bound organelles composed of rRNA and proteins, found in both prokaryotes and eukaryotes. They are essential for protein synthesis.

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Golgi Apparatus

A membrane-bound organelle involved in modifying, packaging, and transporting proteins and lipids within the cell.

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Cell Membrane

A double membrane composed of lipids and proteins, found in both plant and animal cells. Acts as a selectively permeable barrier, controlling what enters and leaves the cell.

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Mitochondria

Oval-shaped, membrane-bound organelles, known as the 'Powerhouse of the Cell'. Perform cellular respiration, creating energy in the form of ATP.

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Peroxisome

A membrane-bound organelle found in the cytoplasm of cells, responsible for breaking down fatty acids and other molecules. It is also involved in detoxification.

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Plastid

Double membrane-bound organelles found in plants, responsible for photosynthesis and storing various substances..They also impart color to plants.

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Vacuole

A membrane-bound sac filled with fluid, found in the cytoplasm of plant cells. They help in maintaining the plant's shape and storing waste products.

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Peroxisome

A membrane-bound sac containing enzymes and found in both plant and animal cells that helps break down lipids by reducing enzymes.

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What is the cell wall?

The rigid outer layer found in plant cells, providing structural support and protection.

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What is the endoplasmic reticulum (ER)?

A membrane-bound organelle present in both plant and animal cells, responsible for synthesizing lipids and proteins.

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What are mitochondria?

A round or oval-shaped organelle, found in both plant and animal cells. It is responsible for producing energy through cellular respiration.

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What is the Golgi apparatus?

A membrane-bound organelle present in both plant and animal cells, involved in packaging and modifying proteins and lipids.

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What are chloroplasts?

A type of organelle found only in plant cells. They are responsible for photosynthesis, producing energy from sunlight.

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What is a vacuole?

A large, fluid-filled sac found in plant cells. It helps maintain cell shape, stores water and nutrients, and supports turgor pressure.

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What are lysosomes?

A membrane-bound vesicle present in both plant and animal cells, containing enzymes that break down waste products.

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What is a nucleolus?

A dense, spherical structure found inside the nucleus of eukaryotic cells. It is involved in the synthesis of ribosomes.

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Study Notes

Cell as the Basic Unit of Life

  • An organism is a living entity made up of one or more cells.
  • Organisms share five fundamental characteristics.
  • Cells are membrane-bound units.
  • The membrane separates the inside and outside the cell.
  • The "dream of a bacterium" is to become two bacteria, demonstrating the goal of replication.
  • Organisms evolve and their populations continue to evolve today.
  • Organisms process genetic information encoded in genes and respond/adjust to their surroundings.
  • Organisms need energy to survive and reproduce (e.g., plants absorb sunlight, animals ingest food).

Biological Levels of Organization

  • Biological levels follow a hierarchy from organelles up to the biosphere (e.g., atom, molecule, organelle, cell, tissue, organ, organ system, organisms, populations, communities, ecosystem, biosphere).
  • Atoms bond to form molecules; these molecules aggregate to form organelles.
  • The simplest living thing is an organelle.
  • The biosphere is the highest level in the organization of living things.

Cell Theory

  • The cell theory details fundamental biological questions (what the basic unit of life is, origin, hereditary information).
  • Cells are the fundamental unit of structure and function in all living things.
  • All organisms are made up of one or more cells.
  • Cells come from pre-existing cells (by cellular division).
  • Cells are essentially the same in chemical composition within the same species.
  • Energy (metabolism and biochemistry) occurs within cells.
  • Cells contain DNA.
  • Cells in similar organisms are typically chemically similar.

Cell Size and Function

  • Cell size is limited by the ratio of surface area to volume.
  • Smaller cells have a higher surface area to volume ratio, which is more efficient, compared to larger cells.
  • Eukaryotic cells are generally bigger than prokaryotic cells.
  • The size of a cell affects the functions and metabolic activities it can undertake.

Eukaryotic Cell Structure

  • Eukaryotic cells compartmentalize their cytoplasm in different organelles (membrane-bound).
  • Organelles, including the nucleus, mitochondrion, vacuoles and lysosomes, enable many metabolic processes to be divided in specific parts of the cell, leading to greater efficiency.

Cell Organelles

  • Nucleus: The largest organelle, the control center; it stores the cell's DNA, which controls the characteristics and functions of cells.
  • Mitochondria: the powerhouses of the cell; involved in energy production (ATP) and respiration.
  • Endoplasmic Reticulum: A transporting system in cells; involved in protein manufacture (rough ER) and lipid production (smooth ER).
  • Golgi Apparatus: responsible for transporting/modifying proteins and lipids for their target locations in and around the cell.
  • Ribosomes: involved in protein synthesis for both animal and plant cells; they are important for the processes of the cell.
  • Lysosomes: They break down or digest unwanted materials and waste from the cell.

Plastids

  • Plastids are membrane-bound organelles that contain pigments giving them a variety of colours.
  • Chloroplasts: store pigments to trap light energy for photosynthesis.
  • Chromoplasts: store pigments to give plants different colours.
  • Leucoplasts: store food and starch.

Cilia and Flagella

  • Cilia are hair-like projections used for movement.
  • Flagella are whip-like projections used for movement.

Centrosomes and Centrioles

  • Centrosomes are important components involved in cell division.
  • Pairs of centrioles make up the centrosome structure.

Vacuoles

  • Vacuoles are fluid-filled organelles enclosed by a membrane.
  • They often store nutrients.

Hypertonic, Hypotonic and Isotonic Solutions

  • Hypertonic: Higher solute concentration outside the cell compared to inside. Water moves out and cell shrinks.
  • Hypotonic: Lower solute concentration outside the cell compared to inside. Water moves in and cell swells.
  • Isotonic: Solute concentration is equal inside and outside the cell; water movement is balanced.

Food Preservation

  • Preservation methods are based on osmosis or diffusion to inhibit bacteria.
  • High-salt and low-pH solutions (vinegar) are used to alter the environment of organisms so that they do not get the nutrients they need to grow effectively.

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Description

Explore the fundamental concepts of biology, focusing on cells as the basic unit of life and the hierarchical organization of biological entities. This quiz covers cell structure, the characteristics of organisms, and the various levels of biological organization from organelles to the biosphere.

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