Topic 1- Key Concepts In Biology Flashcards
What are all things made of?
Cells
What’s a eukaryotic cell?
Example
Eukaryotic cells are complex
Eg- animal , plant cells
What’s a prokaryotic cell?
Example-
Prokaryotic cells are smaller and simpler.
Example- bacteria cell
What’s a prokaryotic cell?
Example-
Prokaryotic cells are smaller and simpler.
Example- bacteria cell
Features of an animal cell and what they do…
Nucleus- contains generic information, controls the activities of the cell.
Mitochondria-where most of the reactions for aerobic respiration takes place.
Ribosomes- involved in translation of genetic material and protein synthesis.
Cytoplasm- where most chemical reactions happen, contain enzymes to aid these reactions.
Cell memberane- holds the cell together and controls what goes in and out
Structures of a plant cell…
What they do and contain within them…
Cell wall- strengthens the cell. Contains cellulose.
Large vacuole- maintains internal pressure of the cell. Contains cell sap.
Chloroplasts - where photosynthesis occurs which makes food for the plant. They contain a green substance called chlorophyll
Subcellular structures of a bacteria cell and what they do.
Ribosomes- involved in translation of genetic material and protein synthesis.
Cell memberane- holds the cell together and controls what goes out and in
Chromosomal DNA- controls the cells activities , floats freely in the cytoplasm
Plasmid DNA- small loops of extra DNA that aren’t part of the chromosome.
Flagellum- long hairlike structure that rotates to make the bacteria move . Move the bacteria away from harm and to useful substances.
What’s a specialised cell?
Examples of specialised cells…
A cell which’s structure makes it adapted to its function
Eg: egg, sperm, ciliated epithelial cells.
How is an egg cell specialised ?
It contains nutrients in its cytoplasm to feed the embryo.
It has a haploid nucleus
After fertilisation, its memberane changes structure to stop sperm getting in so the offspring has the right amount of DNA
What’s the function of an egg cell?
The function of an egg cell is to carry female dna and to nourish the developing embryo in its early stages
What’s the function of a sperm cell?
The function of a sperm celll is to transport the males DNA to the females egg.
How is a sperm cell specialised?
- A sperm cell has a long tail so it can swim to the egg.
- It has mitochondria in the middle to provide energy through respiration.
- It has an acrosome in its head which contains enzymes needed to digest its way through the egg cells membrane.
- Has a haploid nucleus
What do epithelial cells do?
They line the surfaces of organs
How is a ciliated epithelial cell specialised?
Example of where they are…
-The cilia beats to move substances in one direction along the surface of a tissue.
-example- the lining of airways have lots of ciliated epithelial cells to help move mucus up to the throat so it can be swallowed and not reach the lungs
When were light microscopes invented?
What can we use light microscopes to see?
Light microscopes were invented in the 1590s. We can use them to see things like nuclei and chloroplasts, to study living cells.
When were electron microscopes invented?
Do they have a higher or lower resolution and magnification than light microscopes?
What can they be used to see?
-Electron microscopes were invented in the 1930s.
-electron microscopes have higher resolutions and magnifications than light microscopes.
-electron microscopes can be used to see subcellular structures, however they can’t see living cells.
What is it important to remember to add when drawing a scientific drawing of a specimen?
Magnification
Scale
Practical for using a light microscope, how to use it ….
1) take a thin slice of specimen.
2)take a clean slide and use a pipette to put a drop of water on it. Use tweezers to place your specimen on the slide.
3)add a drop of stain if your specimen is colourless, this makes it easier to see.
4)place a cover at one end of the specimen, holding it at an angle with a mounted needle then lower it onto the slide. Press down gently ensuring there are no air bubbles trapped under it.
5) select the lowest power objective lens.
6) use the course adjustment knob to move the stage up so the slide is just underneath the objective lens.
7) adjust the focus with the fine adjustment knob.
8) if needed, swaps to a high- powered objective lens.
How to workout out the total magnification?
Magnification = eyepiece lens mag X objective lens mag
Another way to measure magnification if you don’t know which lenses were used…
Magnification = image size / real size
Formula triangle for image size magnification and real size …
If we’re estimating , what do we always round to?
1 signifcant figure
What’s the order of a nanometer picometer milimeter and micrometer from smallest to largest.
Picometer
Nanometer
Micrometer
Millimeter
Definition of a catalyst?
A catalyst is a substance which increases the speed of a reaction without being changed or used up in the reaction.
What is the substrate?
The substrate is the molecule involved in the reaction which fits into the active site of the enzyme.
What’s the activity site of an enzyme?
The active site of an enzyme is the part where it joins into the substrate to catalyse the reaction.
What Do we say when enzymes only work with one substrate?
They have high specifity for their substrate.
What is necessary for enzymes to work.
What do we call this theory?
- the substrate has to fit into the active site, we call this the lock and key theory.
What is the temp or ph called when the enzyme is the most active ?
Optimum temperature/ pH