Questions and Answers
Cells are the building blocks of all plants and ______.
animals
Fluid between cells is called ______ fluid.
interstitial
The cell membrane is made up of a double layer of ______ molecules.
phospholipid
Two classes of cells in the human body are sex cells and ______ cells.
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Membrane proteins can be classified into integral proteins and ______ proteins.
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Cytology is the study of cell ______ and function.
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The cell membrane selectively transports nutrients into and ______ out of the cell.
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The smallest units that perform all vital physiological ______ are cells.
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DNA carries instructions to produce every ______ in the body.
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The DNA instructions for one protein make up a ______.
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The chemical language of DNA instructions is the genetic ______.
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Every group of three bases is known as the ______ code.
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The first step in protein production is ______ activation.
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RNA polymerase copies the complete code for the protein onto a strand of messenger ______.
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In the resulting mRNA strand, each group of 3 nucleotides is a ______ representing one amino acid.
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Translation begins when an mRNA strand is bound between a small and a large ______ unit.
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Cells in a malignant tumor spread into surrounding tissues and start new tumors, a process known as ______.
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An illness that disrupts normal cellular controls and produces malignant cells is called ______.
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Mutated genes that disrupt normal cellular controls are known as ______.
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Cancers often begin where ______ are dividing rapidly.
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All your body cells (except sex cells) contain the same ______ chromosomes.
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A human being grows from 1 cell to ______ cells by cell division.
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Most of a cell’s life is spent in a non-dividing state called ______.
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For body cells to divide, their genetic material must be duplicated exactly in a process called ______.
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Mitosis occurs in ______ stages.
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The second stage of mitosis is called ______.
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During anaphase, chromosomes pull apart into ______ daughter chromosomes.
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Cytokinesis is the division of the ______ of the cell into 2 daughter cells.
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A ______ tumor is contained and not life threatening.
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Anchoring proteins attach the cell membrane to inside or outside ______.
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Recognition proteins label cells as normal or abnormal to the ______ system.
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Enzymes catalyze reactions inside or outside the ______.
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Carrier proteins transport ______ through the cell membrane using energy.
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The two components of cytoplasm are cytosol and ______.
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Microvilli are finger-shaped projections that increase surface area for ______.
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Ribosomes carry out orders from the nucleus for ______ synthesis.
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Cilia are long extensions of the cell membrane that move ______ across the cell surface.
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Study Notes
Cellular Level of Organization
- Cell theory established by Robert Hooke in 1665 outlines that cells are the fundamental units of life, originating from preexisting cells, and maintaining homeostasis.
- Two classes of cells in the human body: sex cells (germ cells) for reproduction, and somatic cells for body functions.
- The cell membrane, or plasma membrane, separates the cytoplasm from the extracellular fluid, functioning as a selective barrier for nutrient transport.
Cell Membrane Structure and Function
- Composed of a phospholipid bilayer with hydrophilic heads facing outward, providing a semi-permeable barrier.
- Membrane proteins classified as integral (embedded) and peripheral (attached to surfaces).
- Six specialized functions of membrane proteins:
- Anchoring proteins: connect the membrane to other structures.
- Recognition proteins: identify normal or abnormal cells to the immune system.
- Enzymes: facilitate chemical reactions on either side of the membrane.
- Receptor proteins: bind to signaling molecules such as hormones.
- Carrier proteins: transport substances across the membrane using energy.
- Channels: pores that manage the flow of water and specific solutes.
Membrane Carbohydrates
- Carbohydrates protrude from the cell membrane, serving roles in:
- Lubrication and protection of the cell surface.
- Anchoring and motility.
- Specific binding for receptors.
- Immune recognition processes.
Cytoplasm and Organelles
- Cytoplasm consists of cytosol (intracellular fluid) and organelles, the functional structures within the cell.
- Six nonmembranous organelles:
- Cytoskeleton: provides structural support and shape.
- Microvilli: projections that enhance absorption surface area.
- Centrioles: aid in cell division by forming spindle fibers.
- Cilia: move fluids across the cell surface.
- Ribosomes: synthesize proteins by translating mRNA instructions.
Genetic Code and Protein Synthesis
- The information for protein synthesis is encoded in DNA, with genes dictating amino acid sequences.
- The genetic code comprises sequences of nitrogenous bases (A, T, C, G); every triplet of bases (codon) corresponds to an amino acid.
- Gene activation begins transcription, where RNA polymerase transcribes DNA into messenger RNA (mRNA) by substituting uracil for thymine.
- After transcription, mRNA exits the nucleus through nuclear pores to ribosomes, where translation occurs to synthesize proteins.
The Cell Life Cycle
- A human develops from a single cell to approximately 75 trillion cells through cell division.
- Cells are primarily in interphase, a non-dividing state where they perform their functions and prepare for division.
- Mitosis consists of four key stages:
- Prophase: Chromosomes condense into chromatids.
- Metaphase: Chromosomes align at the cell's center (metaphase plate).
- Anaphase: Sister chromatids separate into daughter chromosomes.
- Telophase: Nuclear membranes reform, and chromosomes decondense, resulting in two nuclei.
Cytokinesis and Cell Division
- Cytokinesis is the final step of cell division, splitting the cytoplasm to create two daughter cells.
- Tumors can develop from unregulated cell growth, with benign tumors remaining contained while malignant tumors (cancer) can spread (metastasis).
- Cancer arises from mutations affecting normal cellular control mechanisms.
Cell Diversity and Differentiation
- Each body cell, except sex cells, contains 46 chromosomes, but differentiation occurs as cells activate specific genes while deactivating others to fulfill specialized functions (e.g., liver cells, neurons).
- Cell diversity results from selective gene expression, establishing distinct cellular roles in tissues.
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Description
This quiz covers key concepts in cell biology, focusing on the structure and functions of cell membranes, organelles, and the nucleus. It also explores the processes of protein synthesis and the cell cycle, including mitosis. Ideal for students learning about cellular organization and function.
