Topic 2 - Cell Structure Flashcards
What are the two main types of organism?
Eukaryotes and prokaryotes
Name the 10 organelles in an animal cell
1) Nucleus
2) Cell membrane
3) Mitochondria
4) Ribosome
5) Smooth Endoplasmic Reticulum
6) Rough Endoplasmic Reticulum
7) Golgi apparatus
8) Lysosome
9) Cytoplasm
10) Nuclear membrane
Name the 14 organelles in a plant cell
1) Nucleus
2) Cell membrane
3) Cell wall
4) Chloroplasts
5) Ribosome
6) Vacuole
7) Smooth Endoplasmic Reticulum
8) Rough Endoplasmic Reticulum
9) Lysosome
10) Golgi apparatus
11) Mitochondria
12) Nuclear envelope
13) Nucleolus
14) Cytoplasm
What is a cell membrane and what is its function?
Cell membrane is made of lipids and proteins and contains receptors that can respond to chemicals like hormones. Regulates the movement of substances in and out of the cell
What is a nucleus and what is its function?
A nucleus is surrounded by a double membrane, where the genetic information is stored in a cell and controls the transcription of DNA. Nucleolus makes ribosomes.
What is a mitochondria and what is its function?
Oval shape, double membrane, inner one folded (cristae), inside is the matrix that contains enzymes involved in respiration. The site of aerobic respiration.
What is a chloroplast and what is its function?
A small flattened structure surrounded by a double membrane. Has membranes inside called thylakoids which are stacked up to form grana which are linked with lamellae. Site of photosynthesis,
What is the Golgi apparatus and what is its function?
A group of fluid filled membrane bound sacs, where proteins and lipids are processed and packaged.
What are Golgi vesicles and what are their function?
Small fluid filled sacs produced by the Golgi apparatus that store lipids, and proteins.
What is a lysosome and what is its function?
A membranous sac containing digestive enzymes that destroy debris and worn out organelles.
What is a ribosome and what is its function?
The site of protein synthesis. Ribosomes have no membrane and float free in the cytoplasm or are attached to RER
What is the Rough Endoplasmic Reticulum (RER) and what is its function?
A system of membranes enclosing a fluid space. The surface is covered in ribosomes and it folds and processes proteins.
What is the Smooth Endoplasmic Reticulum (SER) and what is its function?
A system of membranes enclosing a fluid filled space. SER synthesises and processes lipids.
What is the Smooth Endoplasmic Reticulum (SER) and what is its function?
A system of membranes enclosing a fluid filled space. SER synthesises and processes lipids.
What is the cell wall and what its is function?
An organelle mainly made of cellulose and chitin (fungi). Gives the cell structure and shape.
What is the vacuole and what is its function?
A membrane bound organelle that contains cell sap. It keeps the shape of the plant cell and keeps the cell rigid.
Describe how epithelial cells are adapted for their function in the small intestine
Villi increase surface area for absorption and microvilli increase surface area further. Lots mitochondria to provide energy for transport.
Describe how red blood cells are adapted for their function
Biconcave shape increases the surface area for oxygen absorption, also no nucleus to make room for haemoglobin.
Describe how sperm cells are adapted for their function
Lots of mitochondria for large amounts of energy.
What is a tissue?
A group of specialised cells that act together to perform a specific function.
What is an organ?
A group of tissues working together.
What are prokaryotes?
Single called organisms.
Name 8 organelles in a prokaryotic cell
1) Flagella
2) Plasmid DNA
3) Cell membrane
4) Cytoplasm
5) Ribosome
6) Cell wall
7) Capsule
8) Free-floating circular loop of DNA
Explain the steps of binary fission
1) DNA and plasmids replicate
2) Cell grows and DNA loops move to opposite poles
3) Cytoplasm divides and 2 daughter cells are produced.
Describe a virus
Non-living, nucleic acid, surrounded by protein that invade cells and reproduce inside.
Describe the structure of a virus
Protein coat (capsid) with attachment proteins.
Describe the process of viral replication
1) Attachment - the virus attaches to the host cell through specific binding between viral proteins and host cell receptors.
2) Penetration and uncoating - After attachment, viruses penetrate the host cell and fuse with the cell membrane. Once inside, the viral capsid is removed (uncoating), releasing the viral nucleic acid.
3) Synthesis of viral components - Viral DNA enters the host cell’s nucleus for replication, using the host’s DNA polymerase enzymes. RNA viruses replicate in the cytoplasm, often using their own RNA-dependent RNA polymerase as host cells do not naturally contain this enzyme. Viral mRNA is used to make viral proteins by the host’s ribosomes.
4) Assembly and maturation - New viral particles are assembled from the newly synthesized nucleic acids and proteins.
5) Release - Newly formed viruses exit the host cell to infect new cells. This can occur through lysis (bursting the cell) or budding (enveloped viruses), where the virus acquires its envelope from the host cell membrane.
What is magnification?
How much bigger the image is compared to the specimen
What is resolution?
How well a microscope distinguishes between 2 points that are close together.
How do optical microscopes form an image?
Using light
Max resolution of an optical microscopes
0.2 micrometers
What organelles could you view under an optical microscope?
Ribosomes
Endoplasmic Reticulum
Lysosomes
Nucleus
Name 2 types of electron microscopes
Transmission electron microscope
Scanning electron microscope
Explain how a TEM works
Use electromagnets to focus beam of electron which are then transmitted through a specimen, denser parts absorb more elections (darker).
Explain how a TEM works
Use electromagnets to focus beam of electron which are then transmitted through a specimen, denser parts absorb more elections (darker).
Advantages and disadvantages of a TEM
+ = high resolution
- = view in vacuum (dead specimen)
Explain how an SEM works
Scan a beam of elections across the specimen, knocks off electrons from specimen, can be 3D
Advantage and disadvantage of SEM
+ = living specimen
- = expensive and very large
What is cell fractionation?
Separating the organelles of a cell by their mass.
What are the 3 main steps of cell fractionation?
Homogenisation
Filtration
Ultracentrifugation
Explain homogenisation
Cell is blended into a solution where the organelles are released into solution (cold, isotonic, pH).
Explain filtration
Solution is filtered to remove any large ell debris or tissue debris.
Explain three steps of ultracentrifugation
1) The cell fragments are put in a centrifuge
2) Ultracentrifugation is when the heaviest organelles sink to the bottom, known as a pellet, of the solution so the top solution that is removed and poured away contains the lightest organelles.
3) The supernatent is spun multiple times until all organises are separated.
