Study Guide for Unit 2, Module 1 (Chapter 4 - A Tour of the Cell)

organelles and cellular components:

Cytoplasm the material or protoplasm within a living cell, excluding the nucleus. plasma membrane/cell membrane a microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm. cell wall a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants, it consists mainly of cellulose. extracellular matrix In biology, the extracellular matrix (ECM) is a collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells. nucleus a dense organelle present in most eukaryotic cells, typically a single rounded structure bounded by a double membrane, containing the genetic material. nucleoid region is an irregularly shaped region within the cell of a prokaryote that contains all or most of the genetic material, called genophore. In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane nucleolus a small dense spherical structure in the nucleus of a cell during interphase. chromosomes i literally ****ing did thiiiiiiisssssss <3 see chapter two question six <3 (determines if you have down syndrome or not i guess fk <3) chromatin the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA. ribosomes>>>> pretty sure i did this but, i'll do again.Do me again <3 >> a minute particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins. rough ER Rough ER is called rough because it has ribosomes attached to its surface. The double membranes of smooth and rough ER form sacs called cisternae. Protein molecules are synthesized and collected in the cisternal space/lumen. When enough proteins have been synthesized, they collect and are pinched off in vesicles. smooth ER a network of tubular membranes within the cytoplasm of the cell, occurring either with a smooth surface (smooth endoplasmic reticulum) or studded with ribosomes (rough endoplasmic reticulum) involved in the transport of materials. Golgi A major organelle in most eukaryotic cells is the structure of membrane-bound sacs called the Golgi apparatus (or Golgi body, Golgi complex, dictyosome). It acts to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. Lysosome an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane. Vacuole a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid. central vacuole The central vacuole is a cellular organelle found in plant cells. It is often the largest organelle in the cell. It is surrounded by a membrane and functions to hold materials and wastes. It also functions to maintain the proper pressure within the plant cells to provide structure and support for the growing plant. chloroplast Animal cells do not have chloroplasts. Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells. The entire process is called photosynthesis and it all depends on the little green chlorophyll molecules in each chloroplast. mitochondria an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It has a double membrane, the inner layer being folded inward to form layers (cristae). cytoskeleton: The cytoskeleton of a cell is made up of microtubules, actin filaments, and intermediate filaments. These structures give the cell its shape and help organize the cell's parts. In addition, they provide a basis for movement and cell division. cilia minute hairlike organelles, identical in structure to flagella, that line the surfaces of certain cells and beat in rhythmic waves, providing locomotion to ciliate protozoans and moving liquids along internal epithelial tissue in animals. flagella lash-like appendage that protrudes from the cell body of certain prokaryotic and eukaryotic cells

pili

<<****ing pills>> <<google says it's a tree seed>> Short, filamentous projections on a bacterial cell, used not for motility but for adhering to other bacterial cell (especially for mating) or to animal cells.

chromosome

<<<< i just fricking defined this > see chapter 3 >>>>>> God you're so fricking cute (if I left it as Fword it was gonna change it to ****. I read all of these in your voice. I hope you don't find this or any of the notes I leave.

capsule

<<i could of wrote the pill definition but i'm not retarded>> a tough sheath or membrane that encloses something in the body, such as a kidney, a lens, or a synovial joint.

endoplasmic reticulum :

<<read this as rectum ****>> <<<<<< a network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane. It usually has ribosomes attached and is involved in protein and lipid synthesis.

cell junction

A cell junction (or intercellular bridge) is a type of structure that exists within the tissue of some multicellular organisms, such as animals. Cell junctions consist of multiprotein complexes that provide contact between neighboring cells or between a cell and the extracellular matrix.

3. Explain how a light microscope works and identify the two most important factors in microscopy.

A mirror at the bottom of the microscope reflects light rays up to the object through a hole in the stage. Objective lenses magnify the image which is made even larger when it is seen through the eyepiece lenses. One of the most critical aspects in optical microscopy is to ensure the specimen is illuminated with light that is bright, glare-free, and evenly dispersed in the field of view 2.The optical components contained within modern microscopes are mounted on a stable, ergonomically designed base that allows rapid exchange, precision centering, and careful alignment between those assemblies that are optically interdependent. Together, the optical and mechanical components of the microscope, including the mounted specimen on a glass micro slide and coverslip, form an optical train with a central axis that traverses the microscope base and stand.

grana

A stacked membranous structure within the chloroplasts of plants and green algae that contains the chlorophyll and is the site of the light reactions of photosynthesis. The saclike membranes that make up grana are known as thylakoids. See more at chloroplast.

9. Polar molecules are hydrophilic (water loving) and will readily dissolve in aqueous (water based) solutions. Nonpolar molecules are hydrophobic (water fearing) and will not dissolve in water. Phospholipids are described as amphipathic molecules, meaning they have both a significant polar region and a significant nonpolar region. Explain how this property (being amphipathic) affects the behavior of phospholipids when placed in water

All of the lipid molecules in cell membranes are amphipathic (or amphiphilic)—that is, they have a hydrophilic ("water-loving") or polar end and a hydrophobic ("water-fearing") or nonpolar end. The most abundant membrane lipids are the phospholipids. These have a polar head group and two hydrophobic hydrocarbon tails.

12.How does DNA direct protein production?

DNA direct protein synthesis by thickening and then unzipping and then being copied onto messenger RNA and then being put onto ribosomes and then being paired with the pairing nucleotide and then being used to create amino acid and then these are transported outside of the cell.

6. Describe what features prokaryotic and eukaryotic cells have in common.

Eukaryotic cells contain membrane-bound organelles, including a nucleus. Eukaryotes can be single-celled or multi-celled, such as you, me, plants, fungi, and insects. Bacteria are an example of prokaryotes. Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle.

11.What distinguishes a free ribosome from a bound ribosome?

Free ribosomes are located in the cytoplasm, and the bound ribosomes are attached to the endoplasmic reticulum. Free ribosomes produce proteins for the cell, while bound ribosomes produce proteins that are transported out of the cell

eukaryotic cell

In addition to the nucleus, eukaryotic cells may contain several other types of organelles, which may include mitochondria, chloroplasts, the endoplasmic reticulum, the Golgi apparatus, and lysosomes. Each of these organelles performs a specific function critical to the cell's survival.

matrix

In biology, matrix (plural: matrices) is the material (or tissue) in animal or plant cells, in which more specialized structures are embedded, and a specific part of the mitochondrion. The internal structure of connective tissues is an extracellular matrix.

intermediate filaments

Intermediate filaments (IFs) are cytoskeletal components found in the cells of vertebrate animal species, and perhaps also in other animals, fungi, plants, and unicellular organisms. They are composed of a family of related proteins sharing common structural and sequence features.

microtubules

Microtubules are filamentous intracellular structures that are responsible for various kinds of movements in all eukaryotic cells. Microtubules are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility.

15.Which two eukaryotic organelles contain their own DNA?

Mitochondria and chloroplasts, which have double-membranes and their own DNA, are believed to have originated from incompletely consumed or invading prokaryotic organisms, which were adopted as a part of the invaded cell. This idea is supported in the Endosymbiotic theory.

8. List all the organelles found in an animal cell and list all the organelles found in a plant cell. Which organelles are found in animal cells, but not in plant cells? Which organelles are found in plant cells but not in animal cells

PLASMA MEMBRANE/ CELL MEMBRANE Structure- a bilipid membraneous layer composed of proteins and carbohydrates. It is fluid like. Function - the cell membrane separates the cell from its external environment, and is selectively permeable (controls what gets in and out). It protects the cell and provides stability. Proteins are found embedded within the plasma membrane, with some extending all the way through in order to transport materials. Carbohydrates are attached to proteins and lipids on the outer lipid layer. . CYTOPLASM Structure - The jelly-like substance composed of mainly water and found between the cell membrane and nucleus. The cytoplasm makes up most of the "body" of a cell and is constantly streaming. Function - Organelles are found here and substances like salts may be dissolved in the cytoplasm. NUCLEUS Structure - The largest organelle in the cell. function necleus in the control center of the cell THE FOLLOWING ORGANELLES ARE FOUND IN BOTH PLANT AND ANIMAL CELLS. "ER" OR ENDOPLASMIC RETICULUM The Endoplasmic Reticulum is a network of membranous canals filled with fluid. They carry materials throughout the cell. The ER is the "transport system" of the cell. There are two types of ER: rough ER and smooth ER. Rough Endoplasmic Reticulum is lined with ribosomes and is rough in appearance and smooth endoplasmic reticulum contains no ribosomes and is smooth in appearance. RIBOSOME Ribosomes are small particles which are found individually in the cytoplasm and also line the membranes of the rough endoplasmic reticulum. Ribosomes produce protein. They could be thought of as "factories" in the cell. GOLGI BODY / APPARATUS Golgi bodies are stacks of flattened membranous stacks (they look like pancakes!). The Golgi Body temporarily stores protein which can then leave the cell via vesiciles pinching off from the Golgi. LYSOSOMES Lysosomes are small sac-like structures surrounded by a single membrane and containing strong digestive enzymes which when released can break down worn out organelles or food. The lysosome is also known as a suicide sac. MITOCHONDRIA The mitochondria are round "tube-like" organelles that are surrounded by a double membrane, with the inner membrane being highly folded. the mitochondria are often referred to as the "powerhouse" of the cell. the mitochondria releases food energy from food molecules to be used by the cell. This process is called respiration. Some cells( muscle cells) require more energy than other cells and so would have many more mitochondria. VACUOLES Vacuoles are fluid filled organelles enclosed by a membrane. They can store materials such as food, water, sugar, minerals and waste products ANIMAL CELLS ORGANELLES NOT FOUND IN PLANT CELLS: CILIA AND FLAGELLA Both cilia and flagella are hair-like organelles which extend from the surface of many animal cells. the structure is identical in both, except that flagella are longer and whiplike and cilia are shorter. There are usually only a few flagella on a cell, while cilia may cover the entire surface of a cell. The function of cilia and flagella ionclude locomotion for one-celled organisms and to move substances over cell surfaces in multi-celled organisms. ORGANELLES AND OTHER FEATURES FOUND ONLY IN PLANT CELLS:. CELL WALL The cell wall is a rigid organelle composed of cellulose and lying just outside the cell membrane. The cell wall gives the plant cell it's box-like shape. it also protects the cell. The cell wall contains pores which allow materials to pass to and from the cell membrane. PLASTIDS Plastids are double membrane bound organelles. It is in plastids that plants make and store food. Plastids are found in the cytoplasm and there are two main types. Leucoplasts - colorless organelles which store starch or other plant nutrients. ( example - starch stored in a potato) Chromoplasts - contain different colored pigments. The most important type of chromoplast is the chloroplast, which contains the green pigment chlorophyll. This is important in the process of photosynthesis.

10.Describe the structure of the plasma membrane, including an explanation of why we describe it as a phospholipid bilayer and a fluid mosaic.

The Fluid Mosaic Model states that membranes are composed of a Phospholipid Bilayer with various protein molecules floating around within it. The 'Fluid' part represents how some parts of the membrane can move around freely, if they are not attached to other parts of the cell.

prokaryotic cell

The Prokaryotic Cell. Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid.

3. CENTRAL VACUOLE

The central vacuole is a large fluid-filled vacuole found in plants

5. Compare/contrast a scanning electron microscope with a transmission electron microscope. Under what circumstances would one choose to use one over the other?

The most important differences between a transmission electron microscope and a scanning electron microscope are: Rather than the broad static beam used in TEM, the SEM beam is focused to a fine point and scans line by line over the sample surface in a rectangular raster patter

4. Explain how an electron microscope works and compare/contrast with a light microscope. What are the benefits and disadvantages of each?

The transmission electron microscope is used to view thin specimens (tissue sections, molecules, etc) through which electrons can pass generating a projection image. The TEM is analogous in many ways to the conventional (compound) light microscope. the electron microscope is better because it can see smaller objects in finer detail.

13.Describe how all the organelles of the endomembrane system are related.

These membranes divide the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes and the cell membrane, among others

endomembrane system

These membranes divide the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes and the cell membrane, among others.

14.What benefit is derived from having lysosomes?

To understand what the lysosome is and what it does, it is first necessary to examine where it fits into the complex system that is the human body. Our bodies are made up of biology's basic building blocks, cells. The body has billions of cells; there are many different cell types, but each cell can be further sub-divided into structures called organelles, which each carry out important functions to make the cell work. Organelles are to cells what organs (such as the heart and liver, for example) are to the whole human body. The lysosome is a type of organelle, and contains specific enzymes (or proteins) which are required to break down and remove materials such as fats and sugars from the cell; it is therefore often referred to as the cell's 'recycling centre'. Despite their diminutive size - about 1/1000th - 1/100th of the width of a human hair - lysosomes play a critical role in processing and transforming the chemical constituents that are used in many cellular processes, for example energy supply, and building cellular structures. Disruption of this small recycling centre can have devastating results for the cell it serves and the body as a whole.

phospholipid

a lipid containing a phosphate group in its molecule, e.g., lecithin.

food vacuole

a vacuole with a digestive function in the protoplasm of a protozoan.

microfilaments

also called actin filaments, are filamentous structures in the cytoplasm of eukaryotic cells and form part of the cytoskeleton. They are primarily composed of polymers of actin, but in cells are modified by and interact with numerous other proteins.

organelle

any of a number of organized or specialized structures within a living cell.

transport vesicle

any vesicle that transports material around the cell. More specifically, transport vesicles are usually refered to those vesicles that transport material from the Endoplasmic Reticulum to the Golgi apparatus or from one part of the Golgi to another.

cristae

each of the partial partitions in a mitochondrion formed by infolding of the inner membrane.

nuclear envelope

is a highly regulated membrane barrier that separates the nucleus from the cytoplasm in eukaryotic cells. It contains a large number of different proteins that have been implicated in chromatin organization and gene regulation.

nuclear pores

is a protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm. In eukaryotic cells, the nucleus is separated from the cytoplasm and surrounded by a nuclear envelope.

cellular respiration

is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.

cell theory

is one of the basic principles of biology. Credit for the formulation of this theory is given to German scientists Theodor Schwann, Matthias Schleiden, and Rudolph Virchow. ... All living organisms are composed of cells. They may be unicellular or multicellular. The cell is the basic unit of life

7. Describe what features differentiate prokaryotic and eukaryotic cells (how are they different?).

see question 6 please.

resolving power

the ability of an optical instrument or type of film to separate or distinguish small or closely adjacent images.

magnification

the action or process of magnifying something or being magnified, especially visually.

photosynthesis

the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.

stroma

the supportive tissue of an epithelial organ, tumor, gonad, etc., consisting of connective tissues and blood vessels