topic 1: eukaryotic cell ultrastructure

not incl protein synthesis

cells of eukaryotes

possess a true nucleus containing genetic materials known as DNA

cells of prokaryotes

lack true nuclei, their genetic material lies freely in the cytoplasm

nuclear envelope is a

double membrane that surrounds nucleus

outer membrane of nuclear envelope is

continuous with RER

inner membrane of nuclear envelope is

in contact with contents of nucleus

dna found in nucleus is

in the form of chromosomes

1 or more nucleoli are formed within the…

nucleoplasm

nucleus control all cellular activities by…

regulating protein and enzyme synthesis

the nucleus is responsible for

nuclear division

the nucleolus is responsible for

the synthesis and partial assembly of ribosomes

cell surface membrane is

phospholipid bilayer with the hydrophobic tails on the interior of the membrane and hydrophilic heads on the exterior

phospholipid is made up of…

a glycerol molecule attached to a phosphate group and 2 fatty acid chains

the function of the csm

barrier between cytoplasm and environment and prevents most water-soluble substances from entering or leaving the cell

centrioles are

cylindrical tube-like structures composed of microtubules

2 centrioles form a

centrosome

centrioles are found

only in animals, in pairs, close to nucleus in cyto or as single structures at the base of cilia and flagella

function of centrioles are to produce

spindle fibres which attach to chromosomes and separate the chromosome during cell division + involved in the formation of the cilia and flagella

ribosomes do not have

membranes

ribosomes are made up of

protein and ribonucleic acid

ribosomes are found

attached to the RER or freely suspended in the cytoplasm

ER consists of a

network of membranous tubes or sacs called cisternae

ER with ribosomes present on its surface

RER

ER that lack ribosomes and more tubular

SER

Golgi Apparatus consists of

a stack of flattened membrane-bound sacs

2 faces of GA are

cis face and trans face

function of GA

chemically modifies, sorts and transports molecules within it for secretion across the cell membrane or for delivery to other parts of the cell

organelle responsible for lysosome formation

GA

lysosomes are

small spherical vesicles, bound by a single membrane, formed from GA

lysosomes contain…

a concentrated mixture of hydrolytic digestive enzymes

function of lysosomes

the digestion of materials taken in by cells (in endocytosis and phagocytosis)

autophagy

digestion of worn out, improperly functioning organelles

autolysis

self-digestion of a cell by the release of lysosome contents within the cells

mitochondrion is

rod or cylinder-shaped organelle that is bound by a double membrane

inner membrane for mito is

extensively folded to form cristae that project into the matrix

materials found within the matrix of mito

hereditary materials like circular DNA, RNA and ribosomes

function of mitochondria

involved in cellular respiration to release energy

inner membrane of chloroplast

gives rise to membranes like lamellae or thylakoids which extend throughout the interior of chloroplast

stroma

gel-like matrix, interior of chloroplast

grana

stacks of thylakoids

intergranal lamellae

joins grana together

chlorophyll is

photosynthetic pigment found inside chloroplasts that make it appear green

vacuole is

fluid-filled structures bound by a single membrane

vesicles are

vacuoles of animal cells, relatively small and less permanent

large central vacuole is

permanent, surrounded by membrane called tonoplast, contains cell sap, in plant cells

cell sap consists of

aqueous solution of dissolved materials such as sugars, ions, organic acids, waste products and pigments

function of chloroplasts

site of photosynthesis

function of vacuoles

store materials for the cell, may contain hydrolytic enzymes and act as lysosomes

cell wall surrounds

plant cell, exterior to cell surface membrane, strong and is permeable

cell wall consists of

cellulose

function of cell wall

mechanical support and protective layer

similarities of plant and animal cells

protoplasm present, chromosomes are composed of linear DNA wound around proteins