Core Concept: Cell structure and organisation Flashcards
Define organelle
a specialised structure with a specific function inside a cell
Define Eukaryote
an organism containing cells that have membrane-bound organelles with DNA in chromosomes within the nucleus
12 components of a generalised animal cell
cell membrane
cytoplasm
smooth endoplasmic reticulum
rough endoplasmic reticulum
golgi body
ribosomes
mitochondria
nucleus
nucleolous
nuclear envelope
nuclear pore
DNA
16 components of a generalised plant cell
cell wall
cell membrane
cytoplasm
smooth endoplasmic reticulum
rough endoplasmic reticulum
golgi body
ribosomes
chloroplasts
Mitochondria
vacuole
tonoplast
nucleus
nucleolous
DNA
nuclear envelope
nuclear pore
From smallest to biggest order nanometre, kilometre, micrometre, metre and millimetre.
nanometre - micrometre - millimetre - metre - kilometre
What size is the nucleus
10-20 micrometres
Describe the components of the nucleus and their function
3 areas 5 components
2 membranes called the nuclear envelope with nuclear pores - allow movement of rRNA and mRNA out of the nucleus the outer membrane is continuous with the RER
neoplasm in the nucleaus which contains chromatin - coils of DNA bound to a protein it condenses into chromosomes
nucleolous - synthesises rRNA
What is a mitochondrion comprised of
5 points
outer cell membrane
inner cell membrane/cristae
matrix
DNA
70s ribosomes
Describe the membrane of the mitochondria and how it is adapted for its function
it has a double membrane which are seperated by the intermembrane space the inner membrane is folded inwards to form the cristae this allows for more surface area for more respiratory enzymes
Describe the shape of a mitochondrion what is its function and how is it adapted for this
it is cylindrical it is the site of aerobic respiration producing ATP it has a higher surface area to volume ratio compared to a sphere it reduces the diffusion distance between te edge and the centre, making aerobic respiration more efficient.
What size is a mitochondrion
1-10 micrometres
7 components of a chloroplast
double membrane
granum
thylakoid
intergranal lamella
stroma
DNA
70s ribosomes
In most plants, what cell has the highest concentration of Chloroplasts
Palisade mesophyll cells
What is the endosymbiotic theory
And what evidence can suggest this
that eukaryotic cells once began as prokaryotic cells and a large cell englufed the mitochondria and chloroplast
they have. a double membrane and have their own 70s ribosomes and DNA so they can produce their own proteins and can replicate
Describe the structure of the endoplasmic reticulum
elaborate system of parallel double membranes formimg a series of flattened sacs with Interconnected fluid filled spaces between them called cisterna
What are the two types of endoplasmic reticulum and their function
Rough ER - has ribosomes on its outer surface and it folds the proteins made there also transports them to golgi
smooth ER - has no ribosomes on it it synthesises, transports and modifies lipids
What cells will have an extensive endoplasmic reticulum
cells that store a high amount of carbohydrates, lipids or proteins like liver cells and secretory cells
What is the function of a ribosome
site of proteins synthesis
What is the different sizes of ribosomes and where would they be found
80s in eukaryotes
70s in prokayotes
Describe the structure of a ribosome where it is assembled and what it is made of
large sub unit on top
small sub unit on the bottom
it is assembled in the nucleolous
and made of rRNA and proteins
Where does the mRNA and tRNA attach on a ribosome
where there are two tRNA binding sites within
where the mRNA binds and is fed through
What is the structure of the Golgi body
compact elaborate system of parallel double membranes formimg a series of flattened sacs called cisternae
What are the functions of the Golgi body
Producing secretory enzymes packaged into secretory vesicles
secreting carbohydrates
producing glycoproteins
transporting and storing lipids
forming lysosomes
What is a lysosome
And its function
single membrane fluid fillled vesicle containing digestive (hydrolytic) enzymes
they can contain and isolate harmful digestive enzymes from the rest of the cell these enzymes can digest material such as a white blood cell that has englufed a bacteria or food
What is are centrioles
And what is its function
two rings of microtubules making hollow cylinders positioned at right angles to each other during cell division they have a role in forming and controlling the spindle fibres
What is a Vacuole
And its function
fluid filled sac bound by a single membrane it contains cell sap, a solution containing amino acids,vitamins, minerals and glucose.
What is a Tonoplast
The tonoplast is a stretchy membrane, and its main function is to protect the vacuole and isolate it from harmful substances. The tonoplast membrane controls ionic and osmotic movement in and around the cell.
What is the structure of a plant cell wall
cellulose is held together in microfibrils which are aggregated into fibres, embedded in a polysaccharide matrix called pectin
What are the functions of a plant cell wall
3 points
Transport - the gaps in the cellulose fibres makes the cell wall fully permeable to water and minerals
Mechanical strength - the microfibrils and thier laminated arrangement make the cell wall strong allowing the cell to be turgid and withstand high pressure potential
communication between cells -cell walls have pits in which strands of cytoplasm called plasmodesmata pass
What are the 2 pathways of water and minerals through the plant route
What does each consist of
apoplast - moves through the cell wall until the casparian strip
symplast - water and mineralls move through the cytoplasm and the plasmodesmata
Differences between plant and animal cells
6 points
plants have a perminent large vacuole - animals have a small tempory one
plants have chloroplasts - animals dont
plants have a cell wall - animals dont
plants dont have centrioles - animals have centrioles
plants have plasmodesmata - animals have no plasmodesmata
plants have startch as an energy store - animals have glycogen as an energy store
Define Prokaryote
a single-celled organism with no membrane bound organelles DNA is free in the cytoplasm
Name 8 components of the generalised prokaryotic cell
flagellum
cell membrane
cytoplasm
peptidoglycan cell wall
mesosome
plasmid
DNA
70s ribosomes
What components are in all prokaryotes
5 points
peptidoglycan cell wall
cell membrane
DNA free in cytoplasm
cytoplasm
70s ribosomes
In eukaryotic and prokaryotic cells Compare the following: length, organelles, DNA, Nuclear envelope, plasmids, cell wall, chloroplasts, mitochondria, mesosome, and ribosomes
length - euk>Pro
organelles - membrane bound in eukaryote not in prokaryotes
DNA - combined with proteins in chromome eukaryotes but free in the cytoplasm in prokarytes
nuclear envelope - in the eukaryote not in prokaryote
plasmids - not in Eukaryote plasmids sometimes in Prokaryote
cell wall - cellulose in plant and chitin in fungi cell wall (Eukaryotes) but in Prokaryote it is peptidoglycan
chloroplasts - in plant Eukaryotes not in Prokaryotes
mitochondria - present in eukaryotes not in prokaryotes
mesosome - not in Eukaryote is in Prokaryote
ribosomes - 80s in Eukaryotes 70s in prokaryotes
Describe the structure of a virus
protein coat called a capsid
and a strand of DNA or RNA
if RNA its called a retro virus
Is a virus living or non living provide an explanation
non living as it does not have any of the living characteristiccs
Define tissue
group of cells with the same structure and function working together
Name three tissue types
epithelium
muscle
connective
Describe the structure of an epithelial tissue
forms a continuous layer covering the internal or external layers of the surfaces of the body no blood vessels but can have nerve endings the cells sit on a basement membrane (made of collagen and protein.
What are the three types/shapes of epithelial tissue
And where they are found
cuboid - one cell thick found in the proximal convuluted tubule
Columnar - eleongated cells with cilia are in oviduct and trachea
squamous - flattened cells on the basement membrane form the walls of the bowmans capsule and alveoli
Name three types of muscle tissue
And their features and functions
3 points
smooth - spindle-shape unstriped involluntary tissues that can contract Rhythmically but less powerfully than skeletal found in skin, in walls of blood vessels, in digestive and respiratory tracts
skeletal - long, striped and voluntary powerful contractions. they attatch to bone and generate locomotion they can tire.
cardiac - striped, short and involuntary muscles only found in the heart that contract rhythmically without stimulation from hormones or nerves and it does not tire
Describe the role of connective tissue
connects, supports or seperates tissues and organs it contains elastic and collagen fibres in an extracellular fluid or matrix between the fibres there is fat storing cells and immune system cells
Define organ
a group of tissues in a structural unit working together and performing a specific function
define system
a group of organs working together with with a particular role
define organism
all systems of the body working together making an organism which is a discrete individual
