Chapter 3

endomembrane system

(endo = within) is a group of membranes and organelles (Figure 3.13) in eukaryotic cells that work together to modify, package, and transport lipids and proteins. It includes the nuclear envelope, lysosomes, vesicles, the endoplasmic reticulum and Golgi apparatus,

nucleus

(plural = nuclei) houses the cell's DNA in the form of chromatin and directs the synthesis of ribosomes and proteins.

nucleolis

(plural = nucleoli), aggregates the ribosomal RNA with associated proteins to assemble the ribosomal subunits that are then transported through the nuclear pores into the cytoplasm.

cilia

(singular = cilium) are present, however, they are many in number and extend along the entire surface of the plasma membrane. They are short, hair-like structures that are used to move entire cells (such as paramecium) or move substances along the outer surface of the cell

flagella

(singular = flagellum) are long, hair-like structures that extend from the plasma membrane and are used to move an entire cell,

Which one of these is NOT true about amino acids?

- Amino acids differ from each other only in number of amino groups

The ______ is the basic unit of life.

cell

lysosomes

cell's "garbage disposal." Digestive enzymes within the lysosomes aid the breakdown of proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles. In single-celled eukaryotes, lysosomes are important for digestion of the food they ingest and the recycling of organelles

ribosomes

cellular structures responsible for protein synthesis. They are NOT organelles but huge and complex macromolecular machines.

cytoplasm

comprises the contents of a cell between the plasma membrane and the nuclear envelope. It is made up of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

Smooth Endoplasmic Reticulum (SER)

continuous with the RER but has few or no ribosomes on its cytoplasmic surface. The SER's functions include synthesis of carbohydrates, lipids (including phospholipids), and steroid hormones; detoxification of medications and poisons; alcohol metabolism; and storage of calcium ions.

nuclear envelope

double-membrane structure that constitutes the outermost portion of the nucleus. Both the inner and outer membranes of the nuclear envelope are phospholipid bilayers. T

electron microscopes

electron microscopes use a beam of electrons instead of a beam of light. Not only does this allow for higher magnification and, thus, more detail (Figure 3.3), it also provides higher resolving power

animal cells

have centrioles and centrosomes (discussed under the cytoskeleton), tight and gap junctions, and desmosomes, whereas plant cells do not.

chloroplasts

have their own DNA and ribosomes. Chloroplasts function in photosynthesis and can be found in eukaryotic cells such as plants and algae.

extracellular matrix

hold the cells together to form a tissue, but it also allows the cells within the tissue to communicate with each other.

intermediate filaments

intermediate diameter and have structural functions, such as maintaining the shape of the cell and anchoring organelles

A typical prokaryotic cell _______ compared to a eukaryotic cell.

is smaller in size by a factor of 100

plasmodesmata

junctions between plant cells, whereas animal cell contacts include tight and gap junctions, and desmosomes.

gap junctions

like plasmodesmata in plant cells in that they are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate

mitochondria

often called the "powerhouses" or "energy factories" of a cell because they are responsible for making adenosine triphosphate (ATP), the cell's main energy-carrying molecule. Oval-shaped, double-membrane organelles (Figure 3.14) that have their own ribosomes and DNA.

peroxisomes

small, round organelles enclosed by single membranes. They carry out oxidation reactions that break down fatty acids and amino acids. They also detoxify many poisons that may enter the body

Rough Endoplasmic Reticulum (RER)

the region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification

microtubules

thickest of the cytoskeletal fibers. guide organelle movement and are the structures that pull chromosomes to their poles during cell division.

microfilaments

thinnest of the cytoskeletal fibers and function in moving cellular components, for example, during cell division. They also maintain the structure of microvilli

light microscopes

.Visible light both passes through and is bent by the lens system to enable the user to see the specimen

Which one of these is NOT correct regarding lipids? (choose all that apply)

A - Lipids are made of monomers D - Steroids are made of glycerine and 4 fatty acids F - Saturated fats are good for you

eukaryotic

A cell characterized by the presence of a nucleus and other membrane-bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi, plants and animals). Plasama membrane, cytoplasm, cytoskeleton, nucleus, ER, flagella and cilia, golgi apparatus, lisosomes, vesicles and vacuoles, ribisomes, mitochondria, chloroplasts

centrosome

A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division. A centrosome has two centrioles.

Which one of these is NOT true about nucleic acids? (choose all that apply)

In DNA, nitrogenous bases of 2 chains face each other and connect via covalent bonds making "ladder-like" structure

How are eukaryotes different from prokaryotes

Prokaryotic cells never have nuclei

intercellular junctions

The connections between one cell and the other. The three types of intercellular contact in animal cells are: desmosomes, gap junctions, and tight junctions.

Golgi apparatus

The sorting, tagging, packaging, and distribution of lipids and proteins take place

desmosomes

act like spot welds between adjacent epithelial cells. They keep cells together in a sheet-like formation in organs and tissues that stretch, like the skin, heart, and muscles.

prokaryotic

Unicellular, no nucleus or membrane bound organelles. Bacteria and archaea cells. prokaryotic cells are significantly smaller than eukaryotic cells 1) a plasma membrane = an outer covering that separates the cell's interior from its surrounding environment; 2) cytoplasm = consisting of a jelly-like region within the cell in which other cellular components are found; 3) DNA = the genetic material of the cell; 4) ribosomes = particles that synthesize proteins.

endosymbiosis

endo-= within) is a relationship in which one organism lives inside the other

plant cells

have a cell wall, chloroplasts, plasmodesmata, and plastids used for storage, and a large central vacuole, whereas animal cells do not.

vesicles and vacuoles

membrane-bound sacs that function in storage and transport. Vacuoles are somewhat larger than vesicles, and the membrane of a vacuole does not fuse with the membranes of other cellular components.

Which of the following is not a component of the endomembrane system?

mitochondrion

cytoskeleton

network of protein fibers that helps to maintain the shape of the cell, secures certain organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently three types of fibers within the cytoskeleton: microfilaments, also known as actin filaments, intermediate filaments, and microtubules

plasma membrane

phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment. The plasma membrane regulates the passage of some substances, such as organic molecules, ions, and water, preventing the passage of some to maintain internal conditions, while actively bringing in or removing others

Which of these do all prokaryotes and eukaryotes share?

plasma membrane

central vacuole

plays a key role in regulating the cell's concentration of water in changing environmental conditions. In plant cells, the liquid inside the central vacuole provides turgor pressure, which is the outward pressure caused by the fluid inside the cell. The central vacuole also functions to store proteins in developing seed cells.

cis face of golgi

receives vesicles

symbiosis

relationship in which organisms from two separate species live in close association and typically exhibit specific adaptations to each other.

Which of the following structures is found both in eukaryotic and prokaryotic cells?

ribosome

cell wall

rigid covering that protects the cell, provides structural support, and gives shape to the cell.

Endoplasmic Reticulum

series of interconnected membranous tubules that collectively modify proteins and synthesize lipids. However, these two functions are performed in separate areas of the endoplasmic reticulum: the rough endoplasmic reticulum (modifies proteins) and the smooth endoplasmic reticulum (modifies lipids).

trans face of golgi

shipping side of golgi

tight junction

watertight seal between two adjacent animal cells typically found in the epithelial tissue that lines internal organs and cavities, and composes most of the skin.