Biology 224- Chp 4

What is the cell theory?

Cells are the fundamental unit of life, all organisms are composed of cells, and all cells come from preexisting cells,

Cells are so small because as cells increase in ________ the surface area also increases, but at a ______ rate.

Volume, lower

What does volume determine in cells?

Their metabolic activity

What does the cells surface area determine?

Rate of transport into and out of the cell.

As a cell grows, its metabolic activity ______, but at a rate faster than the increase in _____ _____.

Increases, surface area

Because cells are so small, what do we need to use to view them?

Technology

Science is a way of ______ and _______ questions.

Asking, viewing

What is the use of scientific principles or knowledge to solve problems?

Technology

What were developed to use and study cells?

Microscopes

What in a microscope makes something larger?

Magnification

What in a microscope makes something clearer? This observes minimum distance seen between two objects and the ability to observe two objects as distinct.

Resolution

Microscopes _______ both the magnification and resolution of objects.

Increase

T or F: Making a small out-of-focus image larger will not increase the resolution.

True

What microscope uses light passing through the sample to observe objects? What is its resolving power?

Light microscope (400-430x)

Resolving power: 200 nm

What microscope coats the surface of the sample with heavy metal stains, then uses an electron beam to scan the surface? In this microscope you obtain more of a 3D view of the surface.

Electron microscope (2 million x)

Resolving power: 0.5 nm resolution

What microscope uses an electron beam passing through the sample to view objects? In this microscope, cells must be killed and stained with heavy metals to block/scatter the electron beam. Those that pass through are focused.

Transmission electron microscope (50 million x)

Resolving power: 50 pm

Where are prokaryotic cells found?

Bacteria and archaea

What cells lack membrane bound organelles, are relatively simple in structure, and are generally smaller than eukaryotic cells?

Prokaryotic cells

What structure is a single membrane that functions in regulating transport?

Regulate transport

What structure of a cell is a peptidoglycan membrane and functions in protection and support?

Cell wall

What cell structure is a polysaccharide and protects and supports the cell?

Capsule

What cell structure is aqueous and functions in heredity/DNA?

Nucleoid

What cell structure is aqueous and functions in biochemical reactions?

Cytoplasm

What cell structure is solid and in RNA and proteins and functions in protein synthesis?

Ribosomes

What cell structure is solid is found on the tail of proteins and functions in movement?

Flagella

What cell possesses membrane bound organelles, are more complex in structure with many organelles, and are larger in size?

Eukaryotic cells

What is an aqueous mixture containing a wide variety of proteins?

Cytoplasm

Many proteins in the cytoplasm are _______, controlling a host of reactions.

Enzymes

Many of these cytoplasmic reactions are the first reactions in important metabolic pathways like _________ and _____ ______ synthesis.

Glycolysis , fatty acid synthesis

What are a series of fibrous organelles which provide an internal skeleton to cells, and perform some other functions as well? Each of the three types of fibers are constructed from many protein monomers.

Cytoskeleton

What structure in the cytoskeleton is the largest and consists of long, hollow tubes of Tubulin contributing to the cytoskeleton?

Microtubules

What are the two differently charged ends of micro tubules? These control their growth from one point to another.

Centrioles and basal bodies

What do microtubules form along which vesicles and chromosomes move using molecular “motors” known as ________?

Cellular roads, Kinesin

What do microtubules form for cellular locomotion?

Cilia and flagella

What do microtubules form for moving chromosomes during nuclear division (mitosis)?

Mitotic spindle

What cytoskeletal element is found only in specialized cells and has more than 50 different types? They are made of thin rods of _______.

Intermediate filaments, keratin

Intermediate filaments are more _____ than other elements of the cytoskeleton because they are not constantly growing and shrinking because they are uncharged.

Stable

What is the function of intermediate filaments?

Maintain cellular shape and provide mechanical strength to cells.

Intermediate filaments line the inside of _______ ________ to ________ _______ (in form of nuclear lamins).

Nuclear membrane, nuclear pores

What are the smallest cytoskeletal structure? They can exist as single elements, in bundles or in networks.

Micro filaments

Micro filaments function in ________ ________ (muscle contraction, cytoplasmic streaming, and pseudopod formation),

Cellular movements

Micro filaments also function in _________ __________ to divide a cell into two daughter cells following mitosis and meiosis.

Cytoplasmic division (cytokinesis)

Where do micro filaments tend to occur? What do they anchor?

Plasma membrane, other proteins

Micro filaments also support the _______ ______ and provide shape and strength to the cell.

Plasma membrane

What is the structure of the nucleus? What is the function of the nucleus?

Double membrane, stores DNA (hereditary/genetic information)

What does the nucleus membrane contain which regulate transport between the nucleus and the cytoplasm?

Thousands of small pores

What are nuclear pores surrounded by?

A complex of 8 large protein granules.

Proteins targeted for the nucleus have a short peptide named….They are “tagged” for import through pores.

Nuclear localization signal

What consists of the genes which code for ribosomal RNA?

Nucleolus

What are rRNAs needed for?

Ribosome construction

The outer of the two nuclear membranes is continuous in some places with the _________ _________.

Endoplasmic reticulum

Why are ribosomes not technically organelles?

They have no membrane

Ribosomes are large and small _____ ________. What are ribosomes composed of?

Solid subunits, 1-3 rRNAs and 20-30+ proteins (prokaryotes).

How many ribosomes are in eukaryotes?

30-50 proteins per subunit.

What are the functions of ribosomes?

Protein synthesis

Where are ribosomes located?

Cytoplasm, endoplasmic reticulum, mitochondria, and chloroplasts

What system is a group of functionally interrelated organelles? This includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, vacuoles, plasma membrane, and vesicles which shuttle materials between these.

Endomembrane system

What in the cell is a single membrane surrounding a central lumen? It consists of tubes and flattened sacs. It can compose up to 10% of the cells total volume. Its membranes, because of the many folds, are many times greater than the plasma membrane.

Endoplasmic reticulum

What in the cell is studded with ribosomes? Ribosomes synthesize proteins which are then transported into the lumen of the ER, segregating them from the cytoplasm?

Rough Endoplasmic reticulum

The proteins in the rough ER can be chemically modified to alter their functions.

They are tagged with a short _______ to mark them for delivery to various organelles by way of vesicles.

peptide

Some proteins in the rough ER have a ______________ chain attached and form __________.

oligosaccharide, glycoproteins

The main function of the rough ER is to….

synthesize/modify proteins (glycoproteins, membrane bound proteins, and proteins destined for various organelles)

Why is the smooth ER smooth? It is more tubular than flattened sacs. It is continuous with sections of the rough ER.

It lacks ribosomes

The smooth ER functions in ___________ of various poisons taken into the body, by modifying them to be more polar and easier to excrete from the cell.

Detoxification

The smooth ER also contains ______ necessary for glycogen and Calcium _______.

Enzymes, metabolism

The smooth ER also synthesizes ________ for membranes and other ______ including steroid hormones,

Phospholipids, lipids

What in the cell is made up of flattened sacs and has a single membrane surrounding central lumen?

Golgi apparatus

In the Golgi apparatus, vesicles transport ______ and ________ from the ER to the cis to medial to trans regions of the Golgi.

Proteins and lipids

The Golgi apparatus adds/modifies what?

Carbohydrate portion of glycoproteins

What function in the Golgi apparatus has proteases that cut large proteins into smaller, functional proteins?

Proteolysis

What function in the Golgi apparatus packages materials into secretory vesicles to be released from the cell?

Secretion

The Golgi apparatus concentrates, _______, and sorts proteins and lipids before being transported to other cellular destinations?

Packages

What in the cell contains large vesicles containing digestive enzymes (Glycoproteins), surrounded by a single membrane?

lysosomes

What is the function of lysosomes?

Digestion via hydrolytic reactions

What lysosomes are formed by vesicles containing hydrolytic (i.e. digestive) enzymes forming from the Golgi?

Primary lysosomes

What type of lysosomes are formed by the fusion of a primary lysosome and a food vacuole (phagosome)?

Secondary lysosome

What structure of the cell is similar to large vesicles? It is a storage site for food or waste materials and maintains turgor/hydrostatic pressure.

Vacuoles

What type of vacuoles do freshwater protists use to excrete excess water? Water diffuses in, then the vacuole contracts, forcing water out via pores.

Contractile vacuoles

What in the cell is vesicle-like and contains enzymes forming specific functions? This includes peroxisomes and glyoxysomes.

Micro bodies

What contains catalase to degrade hydrogen peroxide? These are synthesized as vesicles from the ER.

Peroxisomes

What is formed as a byproduct of many types of reactions but in high levels is toxic?

Hydrogen peroxide

What contain enzymes for specific reactions and found primarily in plant seeds? They convert stored lipids into carbohydrates for growth.

Glyoxysomes

What is part of the endomembrane system that surrounds the cell and divides it from the external environment?

Plasma membrane

What are the functions of the plasma membrane?

Membrane transport, cell signaling, cell adhesion/recognition

What function of the cell is that everything leaving and entering the cell must pass through the plasma membrane? What fill this role?

Membrane transport, protein transporters

What function of the plasma membrane is when cells communicate with each other and the external environment? What fill this role?

Cell signaling, hormones

What function of the cell membrane is when multicellular org sismos need a way to hold cells together and recognize eachother?

Cell adhesion and recognition

What are the two semiautonomous organelles?

Mitochondria (cellular respiration) and chloroplasts (photosynthesis)

Mitochondria and chloroplasts can divide….and contain their own….

Divide independently of the cell and contain their own DNA and ribosomes

What is the structure of the mitochondria?

Double membrane: Two membranes, two spaces

What is the function of the mitochondria?

Convert energy in organic molecules into ATP.

_______ __________ begins in the cytoplasm with _________.

Cellular respiration, glycolysis

Cellular respiration continues in the ___________ with what cycles?

Mitochondria, Krebs Cycle and Electron Transport

The end product in cellular respiration is ______, a modified nucleotide which has a high energy content.

ATP

What is used to do most types of cellular work?

ATP

What is the structure of chloroplasts?

Inner, outer, and thylakoid

What is the function of chloroplasts?

Photosynthesis

What is the photosynthetic pigment embedded within internal stacks of membranes which chloroplasts contain?

Thylakoids

Thylakoid membranes are distinctive; only ____% __________ content.

10% phospholipid

What is the fluid surrounding thylakoids?

Stroma