Cells and Cell Transport Flashcards
What is typically in a prokaryotic cell?
murein cell wall
cell membrane
circular DNA
ribosomes
cytoplasm
What will SOMETIMES be in a prokaryotic cell?
• capsid
• flagellum
• plasmid
What are some differences between eukaryotic and prokaryotic cells?
• eukaryotic have nuclei
• 70s ribosomes in prokaryotic cell
• linear dna in eukaryotic
• prokaryotic organelles aren’t membrane bound
what is binary fission?
How prokaryotic cells reproduce (asexually)
they divide into two daughter cells
they form two cells then four and keep doubling
What is the nucleus?
contain generic material and DNA which determines the shape and function of the cell
it controls protein synthesis
what is surrounding the nucleus?
The nuclear envelope and nuclear pores
What are ribosomes
small organelles made of protein and rRNA
can be inside cytoplasm or on RER
What is the function of ribosomes
used in protein synthesis joining amino acids together
What is the rough endoplasmic reticulum?
Has ribosomes on its surface that produce secretory proteins
these proteins are then sent to Golgi for packaging
What is the Smooth endoplasmic reticulum
doesnt have ribosomes
produces and transport lipids
What are the Golgi apparatus/vesicles?
• apparatus adds carbohydrates to proteins received from the RER to form glycoproteins
• package proteins into vesicles for secretion
• produces lysosomes that release
lysozymes
What are Lysosomes?
sacs containing hydrolytic enzymes
these need to be kept away from the rest of the cell as they will destroy it
What are the functions of lysosomes?
Relese emzymes out the cell which digest material taken in by phagocytosis
What is the function Mitochondria?
involved in aerobic respiration which produces ATP
Describe the mitochondria
- bound by two membranes
- inter membrane space between outer and inner fold membrane
- cristae = folds of the inner membrane
What is the the function of the matrix in a mitochondria
contains enzymes for respiration and ribosomes and DNA
Which cells contain chloroplasts?
photosynthetic plant cells and algae
What is the stroma
- surround chloroplasts and contain enzymes sugar and starch (its like the cytoplasm)
What is the function of thylakoids
form stacks called grana
- they provide a large surface area for chlorophyll molecules to absorb light
What is the function of the cell wall?
provides strength and support to the cell
- has cellulose and microfibrils
What is the function of the vacuole?
contains soluble sugars salts and pigment
What are tissues?
group of similar cells that perform a specific function
they have a common origin
What is an organ?
a structure containing different tissues, which has a specific function
What is a system?
contains two or more organs
What is the function of epithelial cells in the small intestine?
absorption and digestion of products
What is the function of microvilli
provides large surface area for absorption of digested food
What is centrifugation?
It separates structures by density
How are cells prepared for centrifugation?
They are broken up by homogenising in an ice-cold isotonic buffer solutions in a blender.
What is the purpose of the solution being ice cold?
The low temperature prevents the action of enzymes that may cause self digestion
Whats the purpose of the isotonic solution?
prevents osmotic movement of water in/out of organelles which may cause them to burst
Why is a buffer solution used?
to maintain the pH so enzymes aren’t denatured
Why is the homogenate filtered?
to remove cell debris that didn’t burst in homogenisation
What happens during spins?
Homogenate spun at low speed and the densest organelle (nuclei) will form a pellet
- solution remaining (supernatant) is then spun again at higher speed (repeated)
What is the orders of organelles that will be obtained during centrifugation?
nucleus
chloriplasts*
cell wall*
mitochondria
endoplasmic reticulum
ribosomes
How does a light microscope work?
•light passed through a stained specemin
How do electron microscope work?
use beam of electrons with a shorter wavelength than light thus providing a greater resolution
How does a transmission electron microscope work?
• beam of electrons is TRANSMITTED through specemin
- specimen should be thin and stained using heavy metal
- they show internal structures
How does a scanning electron microscope work?
• electron beam SCANNED across specimen
- specimen coated with thin film of heavy metal
- provide 3D image
- lower resolution than TEM
What js the equation for magnification
magnification = image size/ actual size
What is in the cell membrane?
- phospholipid bilayer and protein
Why is the cell membrane described as a fluid mosaic model?
- phospholipid molecules are constantly moving (fluid)
- protein molecules unevenly distributed through membrane (mosaic)
What can/cant easily pass through the phospholipid bilayer?
- lipid soluble molecules can pass quickly
- water soluble ions and polar molecules cant pass thru easily and need channel:carrier proteins
Whats the function of cholesterol?
provides strength to the membrane and restricts movement of phospholipids so its less fluid and less ions are lost
What is the golgi made of
flattened membrane sacs
Where are lysosomes formed
golgi
What are microvilli
folds in a membrane
