Bio Exam #2-Chapter 6

two types of cells

prokaryotic and eukaryotic

4 basic features of all cells

plasma membrane, cytosol, chromosomes, ribosomes

chromosomes

carry genes

cytosol

semifluid substance

4 things prokaryotic cells are known by

no nucleus, DNA in nucleoid, no membrane-bound organelles, cytoplasm bound by the plasma membrane

nucleoid

DNA in an unbound region

cytoplasm

semi-fluid of plasmic fluid

Eukaryotic cells have 3 characteristics

DNA in a nucleus that is bounded by a double membrane, membrane-bound organelles, cytoplasm in the region between the plasma membrane and nucleus

which type of cell is larger

eukaryotic cells

endogenous

created within the cell

exogenous

created without the cell

plasma membrane

selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell

why does a cell want a high surface area to volume ratio

it required less energy to transport things through the cell when the surface area is high

organelles

internal membranes in a eukaryotic cell that divide the cell into compartments

biological membranes

double layer of phospholipids and other lipids

nucleus

contains most of the dna in a eukaryotic cell

ribosomes

use the information from the DNA to make proteins, complex and made of ribosomal RNA (rRNA) and protein

nuclear envelope

encloses the nucleus, separating it from the cytoplasm, is a double membrane that contain a lipid bilayer

pore complex

pore lined structure that regulates the entry and exit of molecules from the nuclues

nuclear lamina

inner lining of nuclear envelope

nucleolus

located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis

6 things the endomembrane system consists of

nuclear envelope, endoplasmic reticulum (smooth and rough), golgi apparatus, lysosomes, vacuoles, plasma membrane

what are the components of the endomembrane system either continuous or connected by

via transfer by vesicles

endoplasmic reticulum

accounts for more than half of the total membrane in many eukaryotic cells

two regions of ER

smooth and rough

4 functions of smooth er

synthesizes lipids, metabolism of carbohydrates, detoxifies drugs and proteins, stores calcium ions

3 functions of rough er

has bound ribosomes which separate glycoproteins, distributes secretory proteins in transport vesicles, is a membrane factory for the cell

glycoproteins

proteins covalently bonded to carbohydrates

golgi apparatus

consists of flattened membrane sacs

3 functions of golgi apparatus

modifies er products, manufactures some macromolecules like polysaccharides, sorts and packages materials into transport vesicles

what does the golgi apparatus do with the packages of material in transport vesicles

tags them with functional groups so they get utilized in proper locations

lyso

breaking down

lysosome

membranous sac of hydrolytic enzymes that can digest macromolecules including the cell’s own organelles and macromolecules

hydrolytic enzymes

made by rough er and then transferred to the golgi apparatus for further processing

vacuoles

large vesicles derived from the er and golgi apparatusf

food vacuoles

formed by phagocytosis

contractile vacuoles

found in many freshwater protists, they pump excess water out of cells

central vacuoles

found in many mature plant cells, they hold organic compounds and water

mitochondria

sites of cellular respiration, is a metabolic process that uses oxygen to generate ATP

ATP

Adenosine Triphosphate

the number of mitochondria in different cells varies depending on

energy needs of the cell

chloroplasts

found in plants and algae, are sites of photosynthesis

peroxisomes

contains enzymes that remove hydrogens from various chemicals for a variety of reasons

peroxisomes produce

hydrogen peroxide but also contain enzymes that convert it to water

cytoskeleton

network of fibers extending throughout the cytoplasm, organizes the cell’s structures and activities anchoring many organelles

3 types of molecular structures in the cytoskeleton

microtubules, microfilaments, intermediate filaments

3 roles of a cytoskeleton

helps support the cell and maintain its shape, it interacts with motor proteins to produce cell motility

2 examples of molor proteins

kinesin or myosin

myosin

motor protein that causes muscle contraction

inside a cell how do vesicles travel

like a train on a track

microtubules

thickest fibers that are hollow rods constructed of dimers of tubulin

microfilaments

thinnest fibers that are solid rods built as a twisted double chained or actin subunits

intermediate filaments

coiled cable fibers with diameters in middle range, are more permanent fixtures that support cell shape and fix organelles in place

4 functions of microtubules

shape the cell, guide movement of organelles, separate chromosomes during cell division, control the beating of flagella and cilia

bundles of microfilaments make up

the core of microvilli of intestinal cells

microfilaments that function in cellular motility contain the protein

myosin in addition to actin

extracellular matrix

made up of glycoproteins such as collagen, proteoglycans, and fibronectin

animal cells are covered by

an extra cellular matrix

extra cellular matrix proteins bind to receptor proteins in the plasma membrane called

integrins

what do integrins do

aid in cell communication

3 types of cell junctions that are common in epithelial tissues

tight junctions, desmosomes, gap junctions

tight junctions

prevent leakage of extracellular fluid

desmosomes

fasten cells together into strong sheets

gap junctions

provide channels between adjacent cells