Cell Biology Flashcards
What is the two key features of a eukaryotic cell?
They have a nucleus, and membrane-bound organelles.
name some examples of eukaryotic cells?
Animal, plant, fungal and algal cells
What is the nucleus?
The nucleus is the largest organelle, it’s typically spherical and it contains the genetic material of the cell. It controls the cells activities and is enclosed by a nuclear envelope.
What is the cell membrane?
The cell membrane is a thin, flexible later, run the outside of the cell. It’s made from phospholipid bilayer and proteins. It separates contents of the cell from the outside environment. It controls entry and exit of materials.
What is the mitochondria?
mitochondria is a rod shaped and the site of aerobic respiration. Surrounded by a double membrane which controls the entry and exit of material into it. The inner membrane is highly folded into cristae under the space in closed by it is the matrix.
What are ribosomes?
Small cytoplasmic granules found in the cytoplasm. They are the site of protein synthesis.
What is rough ER?
3-D system of sheets like membranes, attached to the outer membrane of the nucleus, but spread throughout the cytoplasm. Rough ER specifically, is covered in ribosomes where proteins synthesise
What is smooth ER?
3-D. System of sheet like membranes, attached to the nucleus but spread throughout the cytoplasm. Smooth ER specifically has no ribosomes and synthesise lipids and carbohydrates.
what is the Golgi apparatus?
stacks of flattened membranes with small, rounded, hollow structures, called vesicles. It processes and packages proteins and lipids, especially proteins, destined to be exported from the cell.
What is a lysosome?
vesicles produced by the Golgi that contain enzymes. I can also contain lysozymes. They also isolate potentially harmful enzymes from the rest of the cell until needed. Also responsible for cell death (auto lysis).
What is a chloroplast?
they are where photosynthesis takes place. They are in class by double membrane and contain thylakoids and which are stuffed into piles called grana. The fluid filled cavity is called the stroma
What is the cell wall?
this is a thick layer outside the cell membrane, used to give the cell strength and rigidity. Implants cell walls are made out of cellulose, alcohols are either cellulose, or glycoprotein, fungal cell walls are made of chitin.
what is the vacuole?
Fluid filled sac pound by a single membrane. Only plant cells have one large permanent vacuole, other organisms may have feeding vacuoles.
What is the difference in chloroplasts with algae cells?
they often have one large chloroplast instead of several, and they differ in shape and size to plant cells.
do fungal cells have chloroplasts?
No
Which eukaryotic cell has a permanent vacuole?
Only plant cells
which animal cell organelles are involved in protein synthesis and transportation?
The nucleus (genetic code to make proteins), ribosomes/rough, ER (synthesise proteins), mitochondria (release energy to synthesise proteins), Golgi body (modifies and packages proteins), Golgi vesicles (transports proteins) and the cell membrane (vesicles transport proteins to it, where it passes through)
What is specialised cells?
Specialise cells adapt their structure to their function, and therefore different specialise cells appear drastically different from each other.
Put these in order of smallest to largest: organ, organ system, tissue, cell, organism.
cell, tissue, organ, organ system, organism
What does every single cell in the body contain?
The same DNA
give some examples of specialised cells
What nerve cells, blood cells, skin cells, sperm cells
how can the same DNA lead to so many different cells?
Differentiation
What is the name of a fertilised egg cell?
Zygote
how does a fertilised egg become a ball of cells?
Cell division, mitosis
when does the process of cell differentiation start in an embryo?
When it’s eight cells big
Why does differentiation happened?
Because genes in the DNA are switched on or off, so they make different proteins
what are stem cells?
Undifferentiated cells
what is produced in mitosis?
Genetically identical daughter cells
How is a red blood cells specialised?
it has a large surface area for more oxygen.
What is specialised about a Palaside cell in a plant?
It’s full of chloroplasts for photosynthesis
How is a root hair cells specialised?
A large surface area for collecting more water/minerals
How is the sperm cells specialised?
It has a tail for swimming, lots of mitochondria for energy, a streamlined head for swimming.
How is a guard cells specialised?
It opens and closes based on water in the cell
How is a nerve cell specialised?
It is long for reaching further
What is the function of white blood cell?
it releases antibodies and engulfs a pathogens
and what special feature does a ciliated epithelium cell have?
cilia = tiny hairs to move mucus out of the airway so anything that catches doesn’t stay
What is the exam technique for specialised cells?
S- Size
S- Shape
S- Surface Area
S- Special Features
O- Organelles
What are the rules for biological drawings?
One simple line, not scribbled, clear labelling, no shading, draw with pencil, one lined, paper, title above drawing, don’t cross labels, and draw to scale
What are the key features of a prokaryotic cell?
they are smaller than a eukaryotic cell, they have no nucleus, no membrane-bound organelles
give an example of a prokaryotic cell
Bacterial
What is the difference between ribosomes in prokaryotic and eukaryotic cells?
in prokaryotic cells they are smaller, 70s but in eukaryotic they are 80s
what organelles are always present in a prokaryotic cell?
Cytoplasm, ribosomes, cell wall, cell membrane, and circular DNA
What structures are only sometimes present in prokaryotic cells?
Plasmids, flagellum, capsules
What is a plasmid?
In prokaryotic cells, small circles of DNA in addition to the circular DNA
What is the flagellum?
A tail like structure, there is usually one or more and they are used for movement
What is the capsule?
Sometimes, in prokaryotic cells, it is a thick polysaccharide later that sticks cells together
In prokaryotic cells, what is the cell wall made from?
murine
What is circular DNA?
The DNA in a prokaryotic cell, not associated with proteins, free in the cytoplasm
what structures do both prokaryotic and eukaryotic cells have?
Cytoplasm, cell membrane, and ribosomes (different sizes)
what is binary fission?
Cell division in prokaryotic cells
What is the first stage in binary fission?
DNA replication
what does DNA replication involve in binary fission?
Exact chromosome copy is made
What is the second stage in binary fission?
Cell elongation
What is the final stage of binary fission?
Cell dividing into two
What type of reproduction is binary fission?
Asexual
What is the formula for binary fission?
total number of bacteria= 2^ number of divisions x bacteria at beginning of growth period
What are some examples of viruses?
Coronavirus, Ebola, and influenza
What are the key aspects of viruses?
they are acellular (contain no cells), they are nonliving particles, they are much smaller than bacteria
what is the nucleic acid core of a virus?
This can be either DNA or RNA and can be single or double stranded
what is the enzyme in the centre of a virus?
RNA viruses have reverse transcriptase
what is the protein capsid in a virus?
The capsid protects the viral genome from the external environment
what is the lipid envelope in a virus?
Usually formed from the membrane phospholipids of a cell they were made in, they are present in some viruses, but not all
What are attachment protein is in a virus?
These have specific shapes which allow them to bind to receptors on target cells in order to infect them
what do viruses not have?
Organelles
Viruses have no organelles, what does this mean in terms of replication?
they must use a host cells organelles to produce new viruses
what must virus is do to reproduce?
Hijack a host cell
What happens after an attachment protein connects with a specific receptor of a target cell membrane?
RNA and reverse transcriptase are injected into the cell by Endo cytosis
after being injected into a host cell, what does the reverse transcriptase do?
Replicate the viral RNA and put into the nucleus
During virus replication, after the viral DNA is put into the nucleus of the host cell what does the host cell do?
it starts to a symbol of DNA and proteins needed for the capsid and lipid envelope
After a virus uses a host cell to create new viral DNA and enzymes, what does it do?
The viral DNA and enzymes leave the cell after constructing a viral envelope from the host membrane.
what happens to a host cell after a virus leaves?
The host cell dies as the virus goes on to infect other cells
what is it called when the virus DNA and protein leave a host cell?
Exocytosis, when the RNA and reverse transcriptase are initially injected into the cell, it’s called endocytosis.
what are the two different types of electron microscope called?
Scanning microscope (SEM), transmission electron microscope (TEM)
What must you consider when deciding which microscope to use?
magnification
Resolution
Preparation
What is magnification?
how much bigger the image is than the specimen
what is resolution?
How well the microscope can distinguish between two points that are close together
what has a high resolution electron or light microscopes?
Electron
why do electron microscopes have a much higher resolving power?
They have a much higher resolving power due to shorter wavelengths of electrons compared to light
Is preparation complicated with a light microscope?
No, it’s relatively straightforward.
How do you prepare a specimen with a light microscope?
-Add a drop of water onto the slide
-obtain a thin section of tissue and place it on top of the drop of water
-Staying with iodine solution
-Lower coverslip using a mounted needle
What is the preparation of an electron microscope like?
Complex preparation, parsley in terms of staining a specimen.
what is required for preparing an electron microscope?
Extremely thin specimens are required (more so TEM), specimens cannot be living as a vacuum is required
How to light microscopes work?
light passes through the specimen, which absorbs some wavelengths and reflects others through the lenses and into eyes. The images, then magnified through two lenses (objective and eyepiece).
how are scanning electron microscope used?
Specimens are coated with a scene layer of metal such as gold or platinum. Electrons are reflected from the surface of the specimen. As a result, 3-D images are produced
what is significant about the SEM microscope?
It is the only kind that can create 3-D images
How does the TEM work?
Is this passes a beam of electrons through a specimen. Don’t the areas of the specimen will absorb more electrons less dense areas allow electrons to pass through.
Electrons are passed through a focused by electromagnet onto a screen or photographic plate. This allows us to see inside the cells and organelles.
What is significant about the TEM?
it is the only microscope that can allow us to see inside cells and organelles
What microscope is the only one that can produced coloured images?
Light microscopes
What is the only microscope that can make images 3-D?
SEM
Which microscopes of the most expensive?
Electron microscopes
Why is the preparation so difficult for electron microscopes?
Specimens must be extremely thin, which requires a complex preparation and staining process
arrange these in terms of size, smallest to largest: micro meter millimetre, nano meter, meter
Nano meter
Micro meter
Millimetre
Meter
What do you have to do to change from meters to millimetres, millimetres to micro meters, micro meters to nanometres?
Times by 1000
What is the equation for magnification?
magnification = image size / actual size
what is the smallest ruler in the world?
stage micrometer
Why must you calibrate an eyepiece graticule?
because it has no units
When calibrating an eyepiece graticule, what do you need to look for?
where the lines of the eyepiece graticule and the stage micrometre lineup
What is the chemical formula for glucose?
C6H12O6
