Topic 1- Key concepts in Biology Flashcards
How are animal cells (Eukaryotic) related to their functions?
- Nucleus- contains the cells genetic material and controls activity
- Cytoplasm- Chemical reactions take place
- Mitochondria- Respiration
- Ribosomes- Protein synthesis
- Cell Membrane- Controls what enters and exits the cell
How are plant cells (Eukaryotic) related to their functions?
- Same as animal cell
- Cell wall- gives structure and protection
- Chloroplasts- Photosynthesis
- Large Permanent Vacuole - structure, stores and balances water
How are bacteria cells (Prokaryotic) related to their functions?
- Circular DNA, and Plasmid DNA- Genetic material of the cell and controls activity
- No membrane bound organelles- cytoplasm has no/ minimal movement
-Flagellum- Movement
-Slimy Capsule- Protection
-Cytoplasm- Chemical reactions - Membrane- Controls what enters/ exits
- Cell wall- Protection
- Pili
- Slimy capsule (protection:against phagocytosis
How is a sperm cell specialised?
- Haploid nucleus- contains (23 chromosomes) information for fertilisation
- Mitochondria (lots)- Energy
- Flagellum- Movement
- Streamline- Movement
- Acrosome- contains digestive enzymes, penetrates egg coat
How is the Egg cell specialised?
- Haploid Nucleus- contains (23 chromosomes) information for fertilisation
- Contains nutrients in the cytoplasm for growth of the early embryo
- Cell membrane changes after fertilisation (prevents another sperm entering)
How are ciliated Epithelial cells specialised?
- Have cilia ( many little hairs) to waft substances such as dust out of us.
- Goblet cells secrete a mucus that pathogens stick to.
How has the microscope have improved?
-Electron microscopes have a higher resolution due to their shorter wavelength
- Enables us to see smaller structures such as organelles
- Better clarity
What is (unit) used to measure cells?
- Micrometer
What is are the parts of a mircroscope?
Eyepeice- Look through to view object
Coarse focus/ fine focus- stage is moved closer/ away from objective lens
Turret- rotates to change magnification lens in use
Stage- flat place for object
Lens- changes magnification
What are the small quantitive units?
Milli = 10^-3
Micro=10^-6
Nano=10^-9
Pico=10^-12
6 Core Practical: Investigate biological specimens using
microscopes, including magnification calculations and labelled
scientific drawings from observations
- Get a thin slice of SPECIMEN
- Using a pipette, place a drop of WATER on the SLIDE to SECURE it
- Add METHYLENE BLUE STAIN to colourless structures, to highlight parts
- Lower cover at 45 DEGREES to prevent AIR BUBBLES
- Start with the lowest power objective lens to find the slide
- Coarse focusing wheel to lift stage and focus
- Use higher power objective lens if needed
- Use Fine focusing wheel to bring cell back into view
What are enzymes?
-A biological catalyst that speed up chemical reactions in our body
-Active sight- binds to and breaks down specific substrates
- Not lock and key, induced fit means that the substrate does not exactly have to fit
How can enzymes be denatured?
- Denatured when their active sight is changed and won’t be able to bind to food molecules.
- pH is too high or low
- Temp is too high or low
What are the effects of temperature on enzymes activity?
- Too high/low enzyme is denatured
- Slightly low, the enzymes are slow as they don’t have enough energy
- Slightly high, less activity as some denature
- Optimum temp around 37°C (body temp)
What are the effects of pH on enzymes activity?
- If it is over or under the optimum, the Enzymes activity decreases
- Denatures at extremes
What are the effects of enzyme concentration on enzymes activity?
- With more enzymes, there is more activity as more substrates can be broken down
- This plateaus if the substrate concentration does not increase.
Core Practical: Investigate the effect of pH on enzyme activity
- Add IODONE solution to dimples/ spot plate
- Add AMYLASE ( enzyme) to test tubes
- Add a pH to one test tube
- Add STARCH to the test tube
- wait 10 seconds
-Use a pipette to drop onto the IODINE - Repeat every 10 seconds until not black ( Starch is broken down)
- Record the time
- Repeat with different pH
Enzymes calculations
Rate = change/ time
or
Rate = 1/time
Why are Enzymes important in the digestion process?
They break down food molecules in order for them to be absorbed into the blood stream (via small intestine)
What does Pepsin/ Protease do?
Breaks down proteins into amino acids
What does Lipase do?
Breaks down Lipids into fatty acids and glycerole
What does carbohydrase do?
Breaks down starch/ carbohydrates into maltose and glucose
How do we test for reducing sugars?
- Add food to a test tube
- Add BENEDICT’S solution and equal parts WATER
- Heat in a water bath
- Will turn from GREEN- YELLOW- RED if there is starch present
How do we test for starch?
- Place iodine on food samples
- will turn orange- BLUE/BLACK
