Biology Lesson 4 Cell Structure Intelligent Design August 12, 2024
A cell is the smallest unit in living organisms. Living organisms can be only one cell or many cells attached together. Cells are the basic building blocks of living organisms.
Cells can join together to form tissues to perform a particular task. Tissues can combine to form an organ that performs a specific job. Several organs can combine together to form an organ system. Finally, several organ systems can combine together to form a living organism.
Two types of cells are Prokaryotic and Eukaryotic.
Biologists use an instrument called a microscope to view living cells because they cannot be seen with the naked eye. The lens of the microscope magnifies the image of the organism and allows its cells to be seen. Light microscopes magnify the image of an object by using a beam of visible light that passes and bends through a lens system to visualize a specimen. Electron microscopes magnify the image of organisms by using an electron beam that passes and bends through a lens system to visualize a specimen. Electron microscopes enable higher magnification and more detailed images.
Antony van Leeuwenhoek observed single celled organisms and their movement using a lens microscope in the 17th century, including bacteria and protozoa. Also in the century, Robert Hooke viewed plant cells from a cork tissue under a lens.
In the 19th century, more powerful lenses were developed that enabled biologists to see inside cells and tissues.
Unified Cell Theory is a biological concept that states that one or more cells makes up all organisms. The cell is the basic unit of life and new cells come from existing cells. However, where did the first cell come from? Without Intelligent Design, scientists are clueless.
All cells have four things: (1) a plasma membrane, an outer covering that separates the cell's interior from its surrounding environment
(2) cytoplasm, a jelly like cytosol in the cell along with other cellular components (3) DNA the cell's genetic material (4) ribosomes which make proteins
Prokaryote Cell is a simple, mostly single celled (unicellular) organism that lacks a nucleus or any other organelle inside the cell membrane
Nucleoid is the cell's central part where the prokaryotic DNA is located The Cell Wall is an extra layer of protection, gives the cell its shape, and prevents dehydration. The capsule layer surrounds the cell wall and enables the cell to attach to surfaces in its environment.
Some prokaryotes also have flagella (long hairlike structure that extends from the cell and used for locomotion). Some also have pili, which exchanges genetic material during conjugation, the process by which one bacterium transfers genetic material to another through direct contact. Some bacteria also have fimbriae used to attach to a host cell.
Cell size is between 0.1 to 5 micrometers, which is much smaller that eukaryotic cells (10-100 micrometers); small size helps cells to be the most efficient
Eukaryotic Cells have a membrane-bound nucleus and several other membrane-bound organelles or sacs such as endoplasmic reticulum, golgi apparatus, chloroplasts, mitochondria, and several rod-shaped chromosomes
Animal Cell Components:
Nucleus: Nuclear envelope: membrane enclosing the nucleus. Protein-lined pores allow material to move in and out
Chromatin: DNA plus associated proteins
Nucleolus: condensed regions where ribosomes are formed
Peroxisome: metabolizes waste
Endoplasmic reticulum Rough: associated with ribosomes; makes secretory and membrane proteins
Smooth: makes lipids
Vacuole: membrane bound sac, larger than vesicle, functions in cellular storage and transport
Mitochondria: produce energy
Cytoplasm: gell-like cytosol inside cell membrane and outside of nucleus.
Golgi apparatus: modifies proteins
Lysosome: digests food and waste materials
Plasma membrane
Microfilaments: fibrous proteins; form the cellular cortex
Intermediate filaments: fibrous proteins that hold organelles in place
Centrosome: microtubule-organizing center
Cytoskeleton Microtubules: form the mitotic spindle and maintain cell shape
Plant Cell Components:
Cell wall maintains cell shape
Plasma membrane
Cytoplasm
Central Vacuole: filled with cell sap that maintains pressure against cell wall
Cytoskeleton: microtubules intermediate filaments microfilaments
Chloroplast site of photosynthesis
Plastid: store pigments
Peroxisome
Mitochondria
Golgi apparatus
Ribosomes
Nucleus: contains chromatin, a nuclear envelope, and a nucleolus, as in an animal cell
Endoplasmic reticulum: smooth and rough
Plasmodesmata: channels connect two plant cells
The Plasma Membrane is the phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the cell's internal content from its surrounding environment, allowing it to regulate what comes in and out of the membrane. Microvilli are the plasma membranes of cells that focus on absorption and fold into finger-like projections (found in small intestines)
Cytoplasm is the entire region between the plasma membrane and the nuclear envelope, containing organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals; cytoplasm is 70-80 percent water, but also contains proteins, glucose, sugars, polysaccharides, amino acids, nucleic acids, fatty acids, and glycerol products
Nucleus is the most important organelle and houses the DNA and directs the making of ribosomes and proteins.
Nuclear Envelope is a double-membrane structure that makes up the nucleus' most outer portion and both layers (inner and outer) are phospholipid bylayers; pores in the envelope allow materials to pass through like ions, molecules, and RNA.
Nucleoplasm is the semi-solid fluid inside the nucleus where the chromatin and nucleolus are located.
Chromosomes are structures within the nucleus that are made up of DNA heredity material (chromatin). In prokaryotes, DNA is one circular chromosome. However, in eukaryotes, chromosomes are linear structures and each cell has the same number of chromosomes in each species of organism.
Chromatin are unwound protein-chromosome complexes during cell growth. Chromosomes only become visible and distinguishable when the cell is ready to divide.
Nucleolus is the darkly staining body within the nucleus that is responsible for assembling ribosome subunits by aggregating ribosomal RNA with associated proteins and transferring them out of the nucleus through pores
Ribosomes are cellular structures responsible for protein synthesis; gets information from mRNA to make proteins. Ribosomes are found in almost every cell.
Mitochondria are the cellular organelles responsible for carrying out cellular respiration and producing ATP (adenosine triphosphate), the cell's main energy carrying molecule
Peroxisomes are small, round membrane bound organelles that contains hydrogen peroxide, oxidizes fatty acids and amino acids, detoxifies many poisons
Vesicles are small, membrane bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus
Vacuoles are membrane bound sacs somewhat larger than a vesicle, which functions in cellular storage and transport and similar to vesicles.
Centrosome is a a region in animal cells (not plant cells) made of two centrioles perpendicular to each other that serves as an organizing center for microtubules and center of origin; replicates before dividing
Lysosomes are organelles in most animals (not most plants); lysosomes are the cell's garbage disposal or digestive component; enzymes break down acids and proteins, lipids, polysaccarides, and worn out organelles
Cell wall is the rigid cell covering composed of various molecules that protects the cell, provides structural support and shape to the cell
Chloroplasts are the plant cell organelle that carries out photosynthesis, which is the series of reactions that use carbon dioxide, water, and light energy to make glucose and oxygen. While plants can make their own food through photosynthesis, animals must obtain food from outside
Chlorophyll is a green pigment that captures light energy that drives the reactions of photosynthesis; in addition to plants, some protists and bacteria contain chlorophyll
Central vacuole is the large plant cell organelle that regulates the cell's storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation
Endomembrane system is the group of membranes and organelles in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins.
Endoplasmic reticulum is a series of interconnected membranous sacs and tubules that collectively modifies proteins and synthesizes lipids; rough and smooth ER
Rough Endoplasmic reticulum has ribosomes attached to its cytoplasmic surface and appears rough in appearance in the microscope; engages in protein modification and phospholipid synthesis
Smooth Endoplasmic reticulum region of ER that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (preservatives, pesticides, medications, and pollutants), and stores calcium ions
Golgi apparatus is a eukaryotic organelle that is comprised of a series of stacked membranes that sort, tags, and packages lipids and proteins for distribution
Lysosomes are organelles in most animals (not most plants); lysosomes are the cell's garbage disposal or digestive component; enzymes break down acids and proteins, lipids, polysaccarides, and worn out organelles; also are part of the endomembrane system; fight pathogens or disease organisms that enter the cell
Cytoskeleton is the protein-fiber network that maintains the cell's shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently
Microfilaments are protein fibers (two globular protein intertwined strands) in the cytoskeleton system that are the narrowest element; it provides rigidity and shape to the cell and enables cellular movements; can disassemble and reform quickly
Intermediate filaments are cytoskeletal components comprised of several fibrous protein intertwined strands that bear tension, supports cell to cell junctions, and anchors cells to extracellular structures
Microtubules are the cytoskeleton's widest element and helps the cell to resist compression, provides a track along which vesicles move through the cell, pulls replicated chromosomes to opposite ends of a dividing cell, and is the structural element of centrioles, flagella, and cilia; can disassemble and reform quickly
Flagella are long, hair-like structures that extend from the plasma membrane and enable the entire cell to move
Cilia are short, hair-like structures that extend from the plasma membrane in large numbers and functions to move an entire cell or move substances along the cell's outer surface
Flagella-cilia (9+2 array) structural arrangement=ring of 9 microtubule doublets surrounding a single microtubule doublet in the center
Extracellular matrix is material secreted from animal or fungal cells that provides mechanical protection and anchoring for the cells in the tissue; allows cells in tissue to communicate with each other
Plasmodesmata (plasmodesma singular) are channels that pass between adjacent plant cells' cell walls, connect their cytoplasm, and allow transport of materials from cell to cell
Tight junction is a protein adherence that creates a tight, firm seal between two adjacent animal cells and prevents leaking
Desmosomes are linkages (or spot welds) between adjacent epithelial animal cells that form when cadherins in the plasma membrane attach to intermediate filaments
Cadherins are short proteins in the plasma membrane that connect to intermediate filaments to create desmosomes and help cells attach together
Gap junctions are channels between two adjacent animal cells that allow ions, nutrients, and low molecular weight substances to pass between cells, enabling the cells to communicate (such as by electric signal)
Connexons (connexins) is an assembly of six protons called connexins that form the pore for the gap junction between the cytoplasm of two adjacent cells
A cell is the smallest unit in living organisms. Living organisms can be only one cell or many cells attached together. Cells are the basic building blocks of living organisms.
Cells can join together to form tissues to perform a particular task. Tissues can combine to form an organ that performs a specific job. Several organs can combine together to form an organ system. Finally, several organ systems can combine together to form a living organism.
Two types of cells are Prokaryotic and Eukaryotic.
Biologists use an instrument called a microscope to view living cells because they cannot be seen with the naked eye. The lens of the microscope magnifies the image of the organism and allows its cells to be seen. Light microscopes magnify the image of an object by using a beam of visible light that passes and bends through a lens system to visualize a specimen. Electron microscopes magnify the image of organisms by using an electron beam that passes and bends through a lens system to visualize a specimen. Electron microscopes enable higher magnification and more detailed images.
Antony van Leeuwenhoek observed single celled organisms and their movement using a lens microscope in the 17th century, including bacteria and protozoa. Also in the century, Robert Hooke viewed plant cells from a cork tissue under a lens.
In the 19th century, more powerful lenses were developed that enabled biologists to see inside cells and tissues.
Unified Cell Theory is a biological concept that states that one or more cells makes up all organisms. The cell is the basic unit of life and new cells come from existing cells. However, where did the first cell come from? Without Intelligent Design, scientists are clueless.
All cells have four things: (1) a plasma membrane, an outer covering that separates the cell's interior from its surrounding environment
(2) cytoplasm, a jelly like cytosol in the cell along with other cellular components (3) DNA the cell's genetic material (4) ribosomes which make proteins
Prokaryote Cell is a simple, mostly single celled (unicellular) organism that lacks a nucleus or any other organelle inside the cell membrane
Nucleoid is the cell's central part where the prokaryotic DNA is located The Cell Wall is an extra layer of protection, gives the cell its shape, and prevents dehydration. The capsule layer surrounds the cell wall and enables the cell to attach to surfaces in its environment.
Some prokaryotes also have flagella (long hairlike structure that extends from the cell and used for locomotion). Some also have pili, which exchanges genetic material during conjugation, the process by which one bacterium transfers genetic material to another through direct contact. Some bacteria also have fimbriae used to attach to a host cell.
Cell size is between 0.1 to 5 micrometers, which is much smaller that eukaryotic cells (10-100 micrometers); small size helps cells to be the most efficient
Eukaryotic Cells have a membrane-bound nucleus and several other membrane-bound organelles or sacs such as endoplasmic reticulum, golgi apparatus, chloroplasts, mitochondria, and several rod-shaped chromosomes
Animal Cell Components:
Nucleus: Nuclear envelope: membrane enclosing the nucleus. Protein-lined pores allow material to move in and out
Chromatin: DNA plus associated proteins
Nucleolus: condensed regions where ribosomes are formed
Peroxisome: metabolizes waste
Endoplasmic reticulum Rough: associated with ribosomes; makes secretory and membrane proteins
Smooth: makes lipids
Vacuole: membrane bound sac, larger than vesicle, functions in cellular storage and transport
Mitochondria: produce energy
Cytoplasm: gell-like cytosol inside cell membrane and outside of nucleus.
Golgi apparatus: modifies proteins
Lysosome: digests food and waste materials
Plasma membrane
Microfilaments: fibrous proteins; form the cellular cortex
Intermediate filaments: fibrous proteins that hold organelles in place
Centrosome: microtubule-organizing center
Cytoskeleton Microtubules: form the mitotic spindle and maintain cell shape
Plant Cell Components:
Cell wall maintains cell shape
Plasma membrane
Cytoplasm
Central Vacuole: filled with cell sap that maintains pressure against cell wall
Cytoskeleton: microtubules intermediate filaments microfilaments
Chloroplast site of photosynthesis
Plastid: store pigments
Peroxisome
Mitochondria
Golgi apparatus
Ribosomes
Nucleus: contains chromatin, a nuclear envelope, and a nucleolus, as in an animal cell
Endoplasmic reticulum: smooth and rough
Plasmodesmata: channels connect two plant cells
The Plasma Membrane is the phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the cell's internal content from its surrounding environment, allowing it to regulate what comes in and out of the membrane. Microvilli are the plasma membranes of cells that focus on absorption and fold into finger-like projections (found in small intestines)
Cytoplasm is the entire region between the plasma membrane and the nuclear envelope, containing organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals; cytoplasm is 70-80 percent water, but also contains proteins, glucose, sugars, polysaccharides, amino acids, nucleic acids, fatty acids, and glycerol products
Nucleus is the most important organelle and houses the DNA and directs the making of ribosomes and proteins.
Nuclear Envelope is a double-membrane structure that makes up the nucleus' most outer portion and both layers (inner and outer) are phospholipid bylayers; pores in the envelope allow materials to pass through like ions, molecules, and RNA.
Nucleoplasm is the semi-solid fluid inside the nucleus where the chromatin and nucleolus are located.
Chromosomes are structures within the nucleus that are made up of DNA heredity material (chromatin). In prokaryotes, DNA is one circular chromosome. However, in eukaryotes, chromosomes are linear structures and each cell has the same number of chromosomes in each species of organism.
Chromatin are unwound protein-chromosome complexes during cell growth. Chromosomes only become visible and distinguishable when the cell is ready to divide.
Nucleolus is the darkly staining body within the nucleus that is responsible for assembling ribosome subunits by aggregating ribosomal RNA with associated proteins and transferring them out of the nucleus through pores
Ribosomes are cellular structures responsible for protein synthesis; gets information from mRNA to make proteins. Ribosomes are found in almost every cell.
Mitochondria are the cellular organelles responsible for carrying out cellular respiration and producing ATP (adenosine triphosphate), the cell's main energy carrying molecule
Peroxisomes are small, round membrane bound organelles that contains hydrogen peroxide, oxidizes fatty acids and amino acids, detoxifies many poisons
Vesicles are small, membrane bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus
Vacuoles are membrane bound sacs somewhat larger than a vesicle, which functions in cellular storage and transport and similar to vesicles.
Centrosome is a a region in animal cells (not plant cells) made of two centrioles perpendicular to each other that serves as an organizing center for microtubules and center of origin; replicates before dividing
Lysosomes are organelles in most animals (not most plants); lysosomes are the cell's garbage disposal or digestive component; enzymes break down acids and proteins, lipids, polysaccarides, and worn out organelles
Cell wall is the rigid cell covering composed of various molecules that protects the cell, provides structural support and shape to the cell
Chloroplasts are the plant cell organelle that carries out photosynthesis, which is the series of reactions that use carbon dioxide, water, and light energy to make glucose and oxygen. While plants can make their own food through photosynthesis, animals must obtain food from outside
Chlorophyll is a green pigment that captures light energy that drives the reactions of photosynthesis; in addition to plants, some protists and bacteria contain chlorophyll
Central vacuole is the large plant cell organelle that regulates the cell's storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation
Endomembrane system is the group of membranes and organelles in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins.
Endoplasmic reticulum is a series of interconnected membranous sacs and tubules that collectively modifies proteins and synthesizes lipids; rough and smooth ER
Rough Endoplasmic reticulum has ribosomes attached to its cytoplasmic surface and appears rough in appearance in the microscope; engages in protein modification and phospholipid synthesis
Smooth Endoplasmic reticulum region of ER that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (preservatives, pesticides, medications, and pollutants), and stores calcium ions
Golgi apparatus is a eukaryotic organelle that is comprised of a series of stacked membranes that sort, tags, and packages lipids and proteins for distribution
Lysosomes are organelles in most animals (not most plants); lysosomes are the cell's garbage disposal or digestive component; enzymes break down acids and proteins, lipids, polysaccarides, and worn out organelles; also are part of the endomembrane system; fight pathogens or disease organisms that enter the cell
Cytoskeleton is the protein-fiber network that maintains the cell's shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently
Microfilaments are protein fibers (two globular protein intertwined strands) in the cytoskeleton system that are the narrowest element; it provides rigidity and shape to the cell and enables cellular movements; can disassemble and reform quickly
Intermediate filaments are cytoskeletal components comprised of several fibrous protein intertwined strands that bear tension, supports cell to cell junctions, and anchors cells to extracellular structures
Microtubules are the cytoskeleton's widest element and helps the cell to resist compression, provides a track along which vesicles move through the cell, pulls replicated chromosomes to opposite ends of a dividing cell, and is the structural element of centrioles, flagella, and cilia; can disassemble and reform quickly
Flagella are long, hair-like structures that extend from the plasma membrane and enable the entire cell to move
Cilia are short, hair-like structures that extend from the plasma membrane in large numbers and functions to move an entire cell or move substances along the cell's outer surface
Flagella-cilia (9+2 array) structural arrangement=ring of 9 microtubule doublets surrounding a single microtubule doublet in the center
Extracellular matrix is material secreted from animal or fungal cells that provides mechanical protection and anchoring for the cells in the tissue; allows cells in tissue to communicate with each other
Plasmodesmata (plasmodesma singular) are channels that pass between adjacent plant cells' cell walls, connect their cytoplasm, and allow transport of materials from cell to cell
Tight junction is a protein adherence that creates a tight, firm seal between two adjacent animal cells and prevents leaking
Desmosomes are linkages (or spot welds) between adjacent epithelial animal cells that form when cadherins in the plasma membrane attach to intermediate filaments
Cadherins are short proteins in the plasma membrane that connect to intermediate filaments to create desmosomes and help cells attach together
Gap junctions are channels between two adjacent animal cells that allow ions, nutrients, and low molecular weight substances to pass between cells, enabling the cells to communicate (such as by electric signal)
Connexons (connexins) is an assembly of six protons called connexins that form the pore for the gap junction between the cytoplasm of two adjacent cells