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Questions and Answers

Which of the following is NOT a primary function of the proteins produced by ribosomes?

  • Formation of cell membrane components
  • Production of hormones
  • Synthesis of ATP (correct)
  • Creation of receptors

Prokaryotic cells contain membrane-bound organelles such as the nucleus and endoplasmic reticulum.

False (B)

What structural feature primarily differentiates eukaryotic cells from prokaryotic cells regarding their DNA organization?

Eukaryotic cells have their DNA organized into coiled, linear strands located within a nucleus, while prokaryotic cells have circular DNA located in the cytoplasm.

The double membrane structure that surrounds the nucleus, allowing communication through nuclear pores, is called the ______ .

<p>nuclear envelope</p> Signup and view all the answers

Match the eukaryotic cell structures with their primary functions:

<p>Nucleus = Contains and protects the cell's DNA Golgi Apparatus = Modifies, sorts, and packages proteins and lipids Mitochondria = Generates ATP through cellular respiration Lysosomes = Breaks down waste materials and cellular debris Endoplasmic Reticulum = Synthesizes and transports proteins and lipids</p> Signup and view all the answers

During cell division, chromatin condenses into which visible structures under a light microscope?

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

Which of the following characteristics is exclusive to eukaryotic cells?

<p>Presence of internal membranes. (C)</p> Signup and view all the answers

Which of the following statements accurately distinguishes between asexual and sexual reproduction in terms of genetic diversity?

<p>Asexual reproduction produces genetically identical clones, while sexual reproduction results in offspring with greater genetic diversity through the fusion of two cells. (B)</p> Signup and view all the answers

Positive feedback mechanisms, crucial for maintaining homeostasis, primarily function by counteracting deviations from a set point and stabilizing internal conditions.

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

How do negative feedback mechanisms contribute to maintaining homeostasis, and why are they considered essential for physiological stability?

<p>Negative feedback mechanisms maintain homeostasis by initiating corrective measures that counteract deviations from a normal value, acting to reset physiological variables. They are essential as they inhibit further changes once the normal value is reached, preventing extreme fluctuations and ensuring stability.</p> Signup and view all the answers

In the context of thermoregulation within the human body, the ______ serves as the control center, processing signals from thermoreceptors and initiating responses to maintain a stable internal temperature.

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

Match the following homeostatic components with their function:

<p>Receptor = Detects changes in the internal or external environment. Control Center = Processes information and sends out instructions. Effector = Carries out the instructions of the control center to adjust the internal environment.</p> Signup and view all the answers

Which of the following is NOT a characteristic that all living things must exhibit?

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

Which of the following scenarios would most directly be affected by a malfunction in the Golgi complex?

<p>A cell's ability to properly modify and package newly synthesized proteins. (D)</p> Signup and view all the answers

Homeostasis refers to a static, unchanging internal environment within an organism.

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

The smooth endoplasmic reticulum (SER) directly guides the production of cell products through embedded ribosomes.

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

Briefly explain how negative feedback contributes to maintaining homeostasis, providing an example.

<p>Negative feedback loops counteract changes in the body to maintain a stable internal environment. For example, if body temperature rises, mechanisms like sweating are activated to lower it back to the normal range.</p> Signup and view all the answers

The basic unit of heredity in living organisms is the _______.

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

If a cell were unable to perform phagocytosis effectively, which organelle's function would be most directly compromised?

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

Within mitochondria, the inner foldings known as ______ increase the membrane surface area available for cellular respiration.

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

Match the following macromolecules with their primary functions:

<p>Proteins = Diverse functions including enzymes, structural components, and hormones Carbohydrates = Primary source of energy and structural support Lipids = Energy storage, insulation, and cell membrane structure Nucleic acids = Storage and transmission of genetic information</p> Signup and view all the answers

Which concept unifies all of biology?

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

Match the following tissue types with their primary function:

<p>Connective tissue = Links organs together Epithelial tissue = Lines surfaces and cavities Muscular tissue = Forms muscles Nervous tissue = Forms the brain, spinal cord, and nerves</p> Signup and view all the answers

A cell is found to have a high concentration of enzymes capable of breaking down macromolecules and old organelles. Which organelle is most likely abundant in this cell?

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

Prokaryotic cells are more complex in structure than eukaryotic cells.

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

Explain the relationship between cells and metabolism in living organisms.

<p>Cells are the basic unit of life where metabolism, the sum of all chemical reactions, occurs, enabling energy production, growth, and maintenance.</p> Signup and view all the answers

Which of the following best describes the complementary roles of the rough endoplasmic reticulum (RER) and the Golgi complex in protein production and processing?

<p>The RER synthesizes proteins, while the Golgi complex modifies and packages them. (B)</p> Signup and view all the answers

Describe how the structure of the mitochondria, particularly the cristae, supports its function in cellular respiration.

<p>The cristae are inner foldings that increase the membrane surface area which allows for more area to occur for cellular respiration.</p> Signup and view all the answers

All cells arise from pre-______ cells.

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

Which of the following is an example of homeostasis in the human body?

<p>Shivering when cold to raise body temperature. (D)</p> Signup and view all the answers

All eukaryotic cells contain the same types and quantity of organelles, regardless of their specific function within a multicellular organism.

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

Which of the following scenarios best exemplifies a negative feedback mechanism within the human body?

<p>After eating a carbohydrate-rich meal, the pancreas releases insulin, which causes cells to absorb glucose from the bloodstream, lowering blood sugar levels. (A)</p> Signup and view all the answers

The primary function of positive feedback loops is to maintain homeostasis by reversing deviations from a set point.

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

Explain how the interaction between the receptor, control center, and effector maintains a stable body temperature when external temperatures drop.

<p>When external temperatures drop:</p> <ol> <li>Receptors in the skin detect decrease in temperature.</li> <li>The control center (hypothalamus in the brain) processes this information.</li> <li>The control center sends signals to effectors such as muscles to cause shivering (generates heat) and blood vessels to constrict (reducing heat loss) to raise the body temperature back to its set point.</li> </ol> Signup and view all the answers

The skeletal system assists in homeostasis by storing ______ which can be released to maintain electrolyte balance in body fluids.

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

Match each organ system with its primary role in maintaining homeostasis:

<p>Respiratory System = Regulates blood pH through CO2 removal Urinary System = Regulates fluid volume and electrolyte balance Cardiovascular System = Transports hormones and nutrients to coordinate body functions Endocrine System = Transports oxygen and nutrients to cells and removes waste.</p> Signup and view all the answers

Which component of the integumentary system is primarily responsible for detecting changes in temperature?

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

The axial skeleton primarily functions to facilitate limb movement and provide attachment points for muscles involved in locomotion.

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

Explain the role of tendons in the muscular system's ability to produce movement.

<p>Tendons are connective tissues that attach muscles to bones. When a muscle contracts, the force is transmitted through the tendon to the bone, causing it to move. Without tendons, the force generated by muscles could not be effectively transferred to the skeletal system to produce movement.</p> Signup and view all the answers

The ______ nervous system is responsible for directing immediate responses to stimuli by coordinating the activities of other organ systems.

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

Match each endocrine gland with its primary hormonal secretion:

<p>Thyroid gland = Thyroxine (T4) Adrenal glands = Cortisol Pancreas = Insulin Ovaries = Estrogen</p> Signup and view all the answers

Flashcards

Ribosomes

Structures that create proteins.

Prokaryotes

Cells that lack a nucleus or other membrane-bound organelles.

Eukaryotes

Cells that contain a nucleus and other membrane-bound organelles.

Nucleus

The control center of the eukaryotic cell, containing DNA.

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Chromosomes

Thread-like structures made of DNA and proteins (histones).

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Nuclear Envelope

Double membrane surrounding the nucleus, allowing communication through pores.

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Chromatin

The loose form of DNA in the nucleus when the cell is undergoing its normal function.

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Skeletal System Function

Provides support, protects tissues, stores minerals, and forms blood.

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Muscular System Function

Produces movement and locomotion, provides support, and generates heat.

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Nervous System Function

Directs immediate responses to stimuli by coordinating organ systems.

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Cardiovascular System Function

Transports cells and dissolved substances like nutrients, wastes, and gases.

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Respiratory System Function

Delivers air for gas exchange between air and circulating blood.

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Homeostasis Definition

All body systems work together to maintain a stable internal environment.

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Receptor Function

Receives the stimulus in a homeostatic control system.

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Control Center Function

Processes the signal and sends instructions to the effector.

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Effector Function

Carries out the instructions from the control center.

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Negative Feedback

Reduces or suppresses the original stimulus to maintain homeostasis.

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Golgi Complex

Modifies proteins and produces lysosomal enzymes within a cell.

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Lysosomes

Organelles containing digestive enzymes that break down macromolecules, old organelles, and invaders.

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Mitochondria

Sites of cellular respiration, providing energy (ATP) by breaking down glucose.

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Mitochondrion

An organelle with inner foldings (cristae) to increase membrane surface for cellular respiration.

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Lysosomes' Function

Organelles used to destroy bacteria and can kill the cell if necessary.

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Endoplasmic Reticulum (ER)

An extensive network of channels connected to the plasma membrane, nuclear envelope, and organelles. It produces proteins, lipids, and carbohydrates.

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Rough Endoplasmic Reticulum (RER)

Contains ribosomes for protein production.

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Smooth Endoplasmic Reticulum (SER)

Lacks ribosomes; involved in phospholipid production and detoxification.

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Tissue

A group of similar cells working together.

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Homeostasis

Maintaining a stable internal environment.

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Systems Integration

Systems work together to maintain equilibrium.

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Biology

The study of life.

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Cell

The basic unit of life.

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Genes

Basic unit of heredity.

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Evolution

The process that creates new species.

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Macromolecules

Proteins, carbohydrates, lipids, and nucleic acids.

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Cells

Smallest units of life that arise from pre-existing cells.

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Metabolism

All chemical reactions within cells.

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Asexual Reproduction

Offspring arise from a single organism, inheriting the genes of that parent only.

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Sexual Reproduction

Fusion of two cells resulting in offspring with genetic variation.

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Positive Feedback

A response that amplifies the initial change, moving away from a set point.

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Study Notes

Lecture 3: The Cell

  • Today's lecture will cover levels of organization, the cell, eukaryotic vs prokaryotic cells, and cell components.
  • The plasma membrane will be covered in more detail later.

Levels of Organization

  • The levels of organization include the chemical, cellular, tissue, organ, system and organismal levels.
  • Atoms combine to form molecules, such as DNA, representing the chemical level.
  • Cells, like smooth muscle cells, make up the cellular level.
  • Tissue refers to a group of similar cells performing a specific function; smooth muscle tissue indicates the tissue level.
  • Organs, such as the stomach, consist of different tissues working together.
  • Organ systems, like the digestive system, comprise multiple organs coordinating to perform complex functions.
  • The organismal level represents the complete living being, integrating all systems.

Cells: The Smallest Living Things

  • The cell theory is a fundamental organizing principle in biology.
  • The cell is the smallest unit of life, capable of functioning independently.
  • All living organisms are composed of cells, making them either unicellular or multicellular.
  • New cells arise only from pre-existing cells through cell division.
  • The two basic types of cells are prokaryotic and eukaryotic.

Prokaryotic vs. Eukaryotic Cells

  • Prokaryotes are simple cells, like bacteria with no nucleus.
  • Eukaryotes are more complex cells and are often part of multicellular organisms, containing a nucleus.
  • Prokaryotic cells are structurally simple.
  • Prokaryotic cells are typically smaller.
  • Prokaryotic cells lack membrane-bound organelles.
  • Bacteria and Archaea are examples of prokaryotic cells.
  • Eukaryotic cells are structurally complex.
  • Eukaryotic cells are larger.
  • Eukaryotic cells have membrane-bound organelles.
  • Plants, animals, fungi and protists are eukaryotes.

Cellular Components

  • All cells have a plasma membrane, cytoplasm, genetic material, ribosomes, and energy requirements.

Plasma Membrane

  • The plasma membrane acts as a selectively permeable barrier.
  • The plasma membrane connects cells together.
  • The plasma membrane facilitates communication through receptors.

Cytoplasm

  • The cytoplasm is the substance inside the cell membrane.
  • If eukaryotic, the cytoplasm includes cytosol and organelles.

Genetic Material (DNA

  • DNA contains the genetic makeup or "blueprint".
  • DNA contains a sequence that determines traits like eye and hair color, personality, and disease susceptibility.

Ribosomes

  • Examples of proteins created by ribosomes: hormones, receptors, and cell membrane components.

Energy Requirements

  • All cells need to produce energy (ATP) to survive.

Eukaryotic Cell Structures

  • Nucleus: control center.
    • The nucleus contains DNA.
      • Nucleolus: Produces components of the ribosomes.
    • Nuclear envelope: Is a double membrane and allows communication via nuclear pores.
      • Chromosomes: threadlike structures made of DNA and histones.
  • Golgi Apparatus: modifies proteins.
  • Mitochondria: the powerhouse of the cell.
    • Cristae: inner membrane folding that provides more membranes.
  • Lysosomes: contain about 40 digestive enzymes that break down molecules invaders.
  • Endoplasmic Reticulum (ER): an extensive network of channels.
    • RER: the rough ER contains ribosomes and guide the production of cell products.
    • SER: the smooth ER lacks ribosomes, involved in production of phospholipids, and is used for detoxification

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