Chapter 4 - Tour of the Cell

What are prokaryotic cells?

What are prokaryotic cells?

A cell with no membrane-enclosed nucleus or organelles.

what types of organisms are prokaryotic?

bacterial and archaea

what is a eukaryotic cells?

cells with membrane enclosed nucleus and organelles.

what organisms are eukaryotic?

all but bacterial and archaea

what are things all types of cells have?

cytosol, chromosomes, ribosomes, and cytoplasm

what is cytosol?

thick, jellylike fluid inside of all cells

what is chromosomes?

gene-carrying structures found in the nucleus of a eukaryotic cell.

what are ribosomes?

cell structure consisting of RNA and protein functioning as the site of protein synthesis in the cytoplasm.

where are ribosomes made in eukaryotes?

nucleolus

what is the cytoplasm?

interior of all cells, but only refers to the area between the nucleus and the plasma membrane in eukaryotic cells.

what is a nucleoid? where is it found?

non-membrane-bounded area where dna is concentrated.

prokaryotes

explain why the size difference of ribosomes in eukaryotes and prokaryotes matter?

the molecular differences are the basis for the action of some antibodies.

what is the fimbriae?

attachment structures on the surface of some prokaryotes

what is the cell wall?

rigid structure outside the plasma membrane (plants)

what is the capsule? what is the purpose of it

jellylike outer coating of many prokaryotes

to help glue the cell to surfaces or other cells in a colony.

what is the flagella? what is it for

locomotion organelles of some bacteria

help propel a cell through its liquid environment

what are the 4 basic functional groups of organelles and structures?

• the nucleus and ribosomes carry out the genetic control of the cell

• organelles involved in the manufacture, distribution, and breakdown of molecules include the endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, and peroxisomes.

• mitochondria in all cells and chloroplasts in plant cells function in energy processing.

• structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell walls.

what structures are present in the plant cell that are not present in animal

plasmodesmata, central vacuole, and chloroplasts

what structures are present in the animals cell that is not found in the plant cells.

centrioles (within the centrosome) and lysosomes.

what is cellular metabolism?

all the chemical activities of a cell

what is plasmodesmata?

cytoplasmic channels through cell walls that connect adjacent cells.

what is a central vacuole?

a compartment that stores water and other chemicals.

what are chloroplasts?

where photosynthesis takes place within a plant cells.

where are ribosomes found in the cell?

free ribosomes are suspended in the cytosol and bound ribosomes are attached to the outside of the endoplasmic reticulum or nuclear envelope.

what are vesicles?

a sac made of membrane in the cytoplasm of a eukaryotic cell

what is in the endomembrane system

nuclear envelope

endoplasmic reticulum

golgi apparatus

lysosomes

plasma membrane

what do the endomembrane system do?

interact in synthesis, distribution, storage and export of molecules.

what is the endoplasmic reticulum (ER).

an extensive network of flattened sacs and tubules.

what is the smooth endoplasmic reticulum?

part of the ER that lacks ribosomes.

what is the rough endoplasmic reticulum?

part of the ER with ribosomes attached that make membrane proteins and secretory proteins.

what does the smooth ER do?

synthesizes lipids and processes toxins.

what does the rough ER do?

produces membranes and ribosomes on its surface make membrane and secretory proteins.

how are membranes made in the Er?

polypeptides destined to be membrane proteins grow from bound ribosomes, they are inserted into the er membrane.

phospholipids are made by enzymes of the rough er and inserted into the membrane.

what is the golgi apparatus

membranous sacs that modify, store, and ship products of the endoplasmic reticulum.

explain how the golgi apparatus ship and recieve things?

• one side serves as the receiving dock from transport vesicles produced by the ER.

• a vesicle fuses with a sac, adding its membrane and contents.

• products of the er are modified as they progress though the stack

• shipping side functions as a depot, dispatching its products in vesicles that bud off and travel to other sites.

what does the golgi do?

modify the carbohydrate portions of glycoproteins made in the er, removing some sugars and substitution others.

what are lysosomes?

membrane-enclosed sacs of digestive enzymes.

where are lysosomes made?

rough ER and processed in the golgi apparatus

what are vacuoles?

large vesicles with many functions

what are central vacuoles and what has it?

plants

area that stores molecules and wastes and facilitates growth.

how is food digested?

lysosomes fuse with food vacuoles, digest the food and nutrients are released into cytosol.

how are lysosomes recycling centers?

a lysosome can fuse with the damaged organelle and dismantle its contents, making organic molecules available for reuse.

how do contractile vacuoles in protist work?

spokes collect water and expels it outside the cells.

what are peroxisomes?

metabolic compartments that do not originate from the endomembrane system.

what do peroxisomes do?

break down fatty acids to be used as cellular fuel and detoxify harmful compounds yielding hydrogen peroxide

what is the mitochondria?

organelles that carry out cellular respiration in nearly all eukaryotic cells

what are the 2 compartments in mitochondria?

intermembrane space and the mitochondria matrix

what is the mitochondrial matrix?

contains the mitochondrial dna, ribosomes, and enzymes.

what is cellular respiration?

process to convert chemical energy of food molecules to ATP

what is the cristae?

folds of mitochondria that increase the membrane’s surface area

what are chloroplasts?

photosynthesizing organelles of plants and algae. double membranes with thin intermembrane space

what is in the inner membrane of cholorplast?

stroma

what is stroma

thick fluid; contains chloroplast dna and ribosomes plus enzymes

what are thylakoids?

network of interconnected sac; suspended in the stroma

what is a granum?

stack of thylakoids

what is the endosymbiont theory?

mitochondria and chloroplasts were formerly small prokaryotes that began living with larger cells.

what is the cytoskeleton?

network of fibers that provides structural support and aids in movement

how does the cytoskeleton aid in movement?

interaction of the cytoskeleton with motor proteins.

what are the 3 main types of fibers?

microfilaments, microtubules, and intermediate filaments.

what are microtubules?

straight, hollow tubes composed of globular proteins called tubulins

where are microtubules grown from?

in animal cells, from the centrosome.

what is the purpose of microtubules?

• shape and support the cell

• tracks along organelles equipped with motor proteins

• guides movement of chromosome when cells divide (cilia and flagella)

what are intermediate filaments?

fibrous proteins that supercoil into cables to reinforce cell shape and anchor some organelles.

what are microfilaments?

solid rods composed mainly of globular proteins called actin, arrange in a twisted double chain.

what does microfilaments do?

form 3d networks just inside the plasma membrane that helps support the cells shape

what causes muscle cells to contract?

myosin interaction

what is the structure of cilia and flagella?

a ring of nine microtubule doublets surrounds a central pair of microtubules ( 9+2 )

what are dyneins and what do they do?

large motor proteins that are attached along each outer microtubule doublet. they walk along an adjacent doublet one side at a time.

what is the extracellular matrix?

meshwork surrounding animal cells which helps hold cells together in tissues and protects and supports the plasma membrane

what are the main components of ecm?

glycoproteins

what is the most abundant glycoprotein in our bodies?

collagen

what are integrins?

transmembrane protein that interconnects the ecm and cytoskeleton.

it transmit signals between the ecm and cytoskeleton.

what do tight junctions do?

bind cells to form leakproof sheets

what do anchoring junctions do?

it rivets cells into strong tissues

what do gap junctions do?

allow ions and small molecules to flow from cell to cell.

what does the cell wall do?

protects and provides skeletal support that helps keep the plant upright.