Key Concepts In Biology Flashcards
Function of cell membrane
Controls what enters and leaves the cell , e.g . Oxygen, carbon dioxide, glucose
Function of nucleus
A large structure that contains genes that control the activities of the cell
Function of cytoplasm
Jelly like substance that fills the cell- many reactions take place here
Mitochondria
Tiny structures where respiration takes place , releasing energy for cell processes
Ribosomes
(Present in the cytoplasm but not visible at this size): where proteins are made (protein synthesis)
Animal cell
Cell membrane Nucleus Cytoplasm Mitochondria Ribosomes
Plant cell
Cell membrane Nucleus Cytoplasm Mitochondria Ribosomes Cell wall Central vacuole Chloroplasts
Bacteria have a simple cell structure. Like animal and plant cell , they have a cell membrane surrounding the cytoplasm. However they do not have a nucleus . These are called prokaryotic cells
Bacteria have …….
Bacterial cell
Chromosomal DNA Cell membrane Ribosomes Plasmid DNA Cell well Flagellum
A single loop of chromosomal DNA lies a free in the cytoplasm.this carries most of the bacterial genes
Controls what enters and leaves the cell
Where proteins are made
Contain additional genes that are not found in chromosomes
For protection , made of different substances to plant cells
To help them move
Egg cell
Haploid cell
Ribosomes
Cell membrane
Mitochondria
Egg cell structure and functions ?
Sperm cell
Haploid nucleus
Acrosome
Mitochondrion
Tail
Sperm cell structures and function ?
Ciliated epithelial cell
Ribosomes
Cytoplasm
Cilia
Mitochondrion
Cell membrane
Nucleus
Cilaited epithelial cell structures and functions
Before microscopes were invented about 350 years ago , people could not see the cell in organisms
Magnification enables you too see plant cells , animals cells and bacterial cells and the structures inside them
Light microscope = uses light to view an object . The greatest possible magnification using a light microscope is about x2000
Electron microscope = uses electrons to view an object. This makes it possible to magnify objects up to x10 million. YOU CAN SEE OBJECTS MORE CLEARLY AND IN FAR MORE DETAIL WITH AND ELECTRON MICROSCOPE THAN WITH A LIGHT MICROSCOPE
When we’re microscopes invented ? And what happened ?
Light microscope ??
Electron microscope ??
Which microscope is better to use as it more clear when viewing cells ?
Calculating maginification
I -------------------------
M R
Measure image in mm
Multiply by 1000 to get measurement in micrometers(um)
How do you calculate image size
How do you calculate magnification
How do you calculate real size
What do you measure image in
What do you multiply by to get measurement in micrometers
1000 millimetres =1 metre 1000 micrometers=1 metre 1000 000 000 nanometres =1 metre 1000 000 000 000 picometres=1 metre 1000 picometres = 1 nanometre 1000 micrometers= 1 millimetre
How millimetre in a metre ? How many micrometers in a metre ? How many nanometers in a metre ? How many picometres in a metre ? How may picometres in a nanometre ? How many micrometers In a millimetre ?
Rate of reaction - temperature
Enzymes are biological catalysts that control reactions in the body
Each enzyme is specific to its substrate and the activity of enzymes is affected by temperature , substrate and concentration and pH
Optimum temperature = enzyme working at its fastest rate
Higher temperature = cause active site to change shape, so it can’t hold the substrate as tightly and the reaction goes more slowly
Lower temperature=Molecules move more slowly . So substrate molecules take longer to fit in and react in ten active site
Very high temperature = active site breaks up and enzyme is denatured
Optimum temperature effects on temperature ?
Higher temperature efffect on temperature ?
Lower temperature effect temperature ?
Very high temperature effect on active site ?
Rate of reaction - substrate concentration
Higher point =Adding more substrate little effect because active site of every enzyme molecule is working
Lower point = not very active site of each enzyme molecule is working , adding more substrate increased rate of reaction
Effect higher point on substrate concentration
Effect lower point on substrate concentration
rate calculations for enzyme activity
Calculate relative rate of reaction for a particular pH, as 1
——
Time
Method can be improved by:
- using more accurate measuring apparatus
-taking the mean of several repeats at each pH to help reduce the effect of random variation
-taking measurements over a narrower range of pH
How do you calculate reaction rate ?
How can you improve this Method ?
Importance of enzymes
Enzymes catalyse reactions that synthesis larger molecules from smaller ones and break down large molecules into smaller ones
Enzymes as catalysts
Enzymes speed up the rate of a chemical reaction. This means they can be used over and over
What do enzymes do ?
Enzymes as catalysts?
Enzymes being transported
Dissolved substances move into and out of cells by diffusion and active Transport . Water moves in and out of cells by osmosis
Diffusion= important in the body . For example, to move oxygen into cells and to remove carbon dioxide
Diffusion= molecules move from higher concentration to lower concentration
Active transport = makes it possible for cells to absorb ions from Very dilute solutions.
Active transport =dissolved molecules move from low concentration to higher concentration
How do dissolved move into and out of cells?
What is diffusion ?
How do molecules move around in diffusion ?
What is active transport?
How do molecules move around in active transport ?
