2.1 Cell Structure Flashcards
What is the cell surface membrane and its function?
The membrane found on the surface of all cells. Made up of phospholipids.
It regulates the movement of substances into and out of the cell.
Receptor molecules on surface allow chemical response ie) hormones.
What is the nucleus and what’s its function?
Large organelle surrounded by a nuclear envelope with pores. It contains chromosomes and a nucleolus
Controls the cell activities and DNA contains the instructions to make proteins
What is a mitochondria and its function?
Oval shaped double membrane, with the inner folded to give a structure called cristae. Inside is the matrix which contains respiratory enzymes.
The site of aerobic respiration and production of ATP.
What is a chloroplast and its function?
Small organelle found in plants. Surrounded by a double membrane it has membranes inside called thylakoids which are stacked to produce grana, suspended in stroma fluid
This is where photosynthesis takes place
What is the Golgi apparatus and its function?
A group of fluid filled membrane bound flattened stacks.
It processes and packages new lipids proteins and lysosomes.
What is the vesicle and its function?
Small fluid filled sac in the cytoplasm that has broken from the Golgi body.
It stores and transports out of the cell the materials made by the Golgi
What is the lysosome and its function?
A type of Golgi vesicle
Contains digestive lysosome enzymes that can be used to break down worn out organelle or invading pathogens.
What is a ribosome and its function?
A small free floating organelle in the cytoplasm. Made of proteins and RNA
The site where proteins are made.
What is the rough endoplasmic reticulum and its function?
A system of membrane enclosed fluid. The surface is covered with ribosomes.
Folds and processes proteins made at the ribosomes
What is the smooth endoplasmic reticulum and its function?
Similar to RER but no ribosomes
Synthesises and processes lipids
What is the cell wall and its function?
A rigid structure which surrounds cells in plants algae and fungi. Made of cellulose (or chitin in fungi)
Supports and provides rigidity to cell
What is the plant vacuole and its function?
A membrane bound organelle in the cytoplasm of cells containing sap- weak sugar and salt solution
Helps maintain the pressure in the cell and increase rigidity
Stops plants wilting
Isolates unwanted chemicals
What is a eukaryote?
More complicated than prokaryotes, all animal plant algae and fungi cells are eukaryotic.
List the component of eukaryotic cells
Cell surface membrane RER SER Nucleus Nucleolus Mitochondrion Lysosome Ribosomes Nuclear envelope Golgi Vesicle Cytoplasm
List the components of plant cells
Cell surface membrane Chloroplast RER Plasmodemata Mitochondria Golgi Vacuole SER Cytoplasm Nucleolus Nucleus Nuclear envelope Ribosome Cell wall
List the component of algal cells
Mitochondria SER RER Golgi Cytoplasm Nucleolus Nucleus Nuclear envelope Chloroplast Cell surface membrane Vacuole Cell wall Ribosomes
What are plasmodemata?
Channels in the cell wall for exchanging substances between cells
What is a chloroplast?
The organelle used in photosynthesis
Show a flowchart of cell organisation
Specialised cells grouped -> tissues
Tissues. -> organs
Organs -> organ systems
What is a tissue?
A specialised group of cells working together to perform a particular function
What are the major structures in a prokaryotic cell?
Cytoplasm contains smaller ribosomes
Phospholipid cell surface membrane
Cell wall adds rigidity and is made of glycoproteins
They have a capsule of mucous to prevent attack by immune systems
Plasmids- small loops of DNA
Free floating DNA to replace the nucleus
Flagella to propel movement
How do you calculate magnification?
Size of real object
How to convert units used in microscopy?
mm. =1 mm
um. =0.001 mm
nm. =0.000001mm
To convert the table, times by 1000 down and divide by 1000 up.
What is resolution?
How well the microscope can distinguish between 2 points
What is magnification?
How much bigger the image is than the specimen.
Eyepiece lens* objective lens= magnification
What is a TEM?
A transmission electron microscope.
Beams of electrons are aimed at the specimen and the denser sections absorb more electrons giving a darker image.
What is an SEM?
A scanning electron microscope.
A beam of electrons are scattered across the specimen to give a 3D image.
What are the advantages of a TEM?
They give high resolution images and can show small images
What are the disadvantages of TEM?
Can only be used on thin specimens
Non living specimens- in a vacuum environment
Black and white images unless false coloured
Artefacts may be produced
Long preparation time
Expensive
What are the advantages of SEM?
Can be used on thick specimens
Gives a 3D image
What are the disadvantages of SEM?
Give low resolution images Non living specimen- vacuum environment Black and white images unless false coloured Artefacts may be produced Long preparation time Expensive
What are microscope artefacts?
They are seen in the microscope but aren’t part of the cell
They may arise due to production and treatment of the specimen.
Cell Fractionation:
What is homogenisation?
Breaking the cells by grinding or blending in a blender to break the cell membrane
(EXAM ANSWERS NEED HOW ITS DONE NOT JUST HOMOGENIZED)
Cell fractionation:
What are the conditions that the solution must be kept in and why?
Cold - to reduce activity of enzymes which break the cell
Isotonic- prevent osmotic loss or gain and osmotic lysis
Buffer- maintain the pH
Cell fractionation:
What is filtration?
The homogenised cell is passed through a gauze to separate large cell debris.
Cell fractionation:
What is ultracentrifugation?
Using a centrifuge to spin the remaining fluid and solution to separate the different organelles at varying speeds. The organelles separate by mass.
Cell fractionation:
In which order are the organelles separated in ultracentrifugation?
In order of mass heaviest to lightest
Nuclei Chloroplast (plants) Mitochondria Lysosomes Endoplasmic reticulum Ribosomes
