Cytology Ch 3 Flashcards
Cell membrane
A selectively permeable membrane that controls what goes in and out of the cell by the presence/ absence of specific protein channels
Nucleus
Contains DNA/ genetic information (information about how to produce proteins and instructions for the function of cells)
Nucleoulus
Where ribosomes are produced
Nuclear envelope
A double membrane around the nucleus with nuclear pores for substances to move into and out of the nucleus
Ribosomes
For protein synthesis. In rough ER and in the cytoplasm
Endoplasmic Reticulum
ER- A system of interconnected tubes that transport molecules.
Rough has ribosomes attached that synthesis proteins which get transported through the ER.
Smooth- Synthesise, store and transports lipids and carbohydrates.
Gogi apparatus
A series of curved tubes closely aligned with vsicals budding off.
Give examples of what the Golgo apparatus does
Adds carbs to proteins forming glycoproteins
produces lysosome and other enzymes that are produced in the pancrease.
modifies and stores lipids
Secretes carbs
lysosome
vesicle containing lysozome, a digestive enzyme that breaks down cells, organelles and pathogens
Structure of Cell wall in plants
Beta glucose forming microfibrils which form fibres, producing cellulose.
How is cell wall in plants adapted to its function
Strong and rigid= mechanical strength, cell doesn’t burt under water pressure when turgid.
Permeable
Structural support
Vacuole
makes cells turgid
stores sugar, amino acid
pigment in colour petals
What organelles does mitochondria contain?
Outer mitochondrial membrane Inner mitochondrial membrane Matrix (proteins, lipids, ribosomes, DNA) Cristae Coiled loop of DNA Ribosome
What organelles are in Chloroplast
Outer chloroplast membrane Inner Chloroplast membrane Grana (block of thylakoids) Stroma (cytoplasm) Coiled loop of DNA Ribosomes
What does thylakoids contain?
Chlorophyll
What is Monera
Bacteria
Is Monera a prokaryote or eukaryote
Prokaryote
Difference between prokaryote and eukaryote
Pro has no nucleus envelope, no membrane bound organelles, 70s (smaller) ribosomes, DNA is not associated with histones.
What organelles are in a Bacteria
Coiled loop of DNA Slime capsule Cell membrane Cell wall Pili Plasmid Cytoplasm 70s Ribosome Mesosome Flagellum
Cell wall made of in plants, fungi and bacteria
Cellulose, chitin, murein
Whats a slime Capsule for
Protection from other cells, stops drying out, bacteria can group together,
Whats pili for
Cell adhesion and conjugation( transfer plasmid)
What is in Virus Structure
Protein Coat
DNA/RNA
Attachment proteins
Sometimes a lipid envelope taken from host
Equation for magnification
Magnification= image/real image
Resolution
the minimum distance apart two objects can be apart in order for them to appear as two separate items.
Why does electron microscope have a greater resolution than light
The beam of electron has a shorter wavelength than light beam
Conditions needed for an electron microscope to work
Beam of electron in vaccum,
specimen needs to be thin, dehydrated, dead,
Differences between Transmission and Scanning EM
Transmission= 2D, greater mag and resolution Scanning= 3D, lower mag and resolution
Cell fractionation
breaking open cells to release contents
Three stages of fractionation
Adding solution, homogenising, and ultracentrifuge
What solution does tissue need to be in for fractionation and why
Ice cold - inactivate enzymes so that organelles are not digested
Buffer- keep pH the same so enzymes are not denatured
Isotonic- ensure water doesn’t move into and out of organelles by osmosis and makes sure the organelles don’t burst or shrivel.
What happens in ultracentrifugation
solution is spun by centrifuge and heaviest organelle is forced to the bottom. (sediment)
The supernatant is filtered put in another test tube and spun again at a faster speed
Rank following from densest to least dense. Mitochondria, ribosome, nucleus, chloroplast
Nucleus, chloroplast, mitochondria and ribosome
Stages of the cell cycle
Interphase, Prophase, metaphase, Anaphase, Telophase and cytokinesis
What happens in Interphase
DNA replicated
What happens in Prophase
Chromosomes become visible, nucleolus breaks down and nuclear envelope disappears and spindle fibre starts to form
What happens in Metaphase
Chromosomes align in the equator of the cell, spindle fibre attaches to the centromere of the chromosomes
What happens in Anaphase
Spindle fibre retracts, pulling apart the two sister choromatids and pulling to opposite poles of the cell
What happens in Telophase
Nuclear envelope forms around each set of chromosomes .
What happens in Cytokinesis
The cell splits in two
How can cancer occur as a result of the cell cycle going wrong?
If there is rapid and uncontrolled cell division it can result to a tumour, and cells not doing their function properly`
How do bacteria’s divide
Binary fission
Is xylem an organ or tissue?
Tissue
Is a blood capillary an organ?
No
Is an artery an organ?
No
Why are arteries and veins organs but not capillaries
Capillaries only have an epithelium cell lining not a muscle wall or elastic wall like veins and artries.
What is the name of the membrane of the vacuole?
Tonoplast
What is Chromatin and where is it found?
Chromatin is the DNA and the histone proteins. The chromosome before it is condensed. It is found in the nucleus.
Where is the endoplasmic reticulum found?
Attached to the nucleus
Where do the products of the endoplasmic reticulum go?
To the gogi apparatus
What is the term for when a cell removes a molecule from the cell?
Exocytosis
What is a tissue?
A group of similar cells working (aggregated) together to perform a specific function.
What is an organ?
A combination of tissues co-ordinates to perform a variety of functions but often one major one.
Do prokaryotes always have flagellum’s?
No, only sometimes
Do prokaryotes always have plasmid?
No, only sometimes.
Do eukaryotes have flagellum’s?
Sometimes
Do eukaryotes have cell walls?
Sometimes
Where are ribosomes produced?
Nucleoulus
Why would you use a TEM microscope to look at a single-celled organism?
High/ better resolution;
Shorter wavelength;
To see internal structures of organelles
Give evidence that supports the theory that mitochondria evolved from prokaryotic cells
Circular DNA, 70s ribosome, no introns and no histones.
Name two structures in a Eukaryotic cell that cannot be identified using an optical microscope
Ribosome, lysosome, mitochondria and endoplasmic reticulum.
How would you make a temporary mount of a piece of plant tissue to observe the position of starch grains in cells when using an optical miscroscope
- Add a drop of water to the slide.
- Place a thin section of plant on slide
- Stain with Iodine from potassium iodine.
- Lower the cover slip with a mounted needle
What happens in Binary fission?
- Replication of the circular DNA and of plasmids
- division of the cytoplasm to produce two daughter cells, each with a single copy of the circular DNA and a variable number of copies of plasmids.
How would you calculate mitotic index?
Number of cells undergoing mitosis/Total number of cells x 100
