sb1 Flashcards
What are some adaptations of sperm cells?
- Many mitrochondria
—> releases energy from respiration for swimming - Acrosome
—> have digestive enzymes which break down outer layers of membrane on egg cell - Tail
—> supports in swimming
How would you prepare a microscope slide to view under a light microscope?
- Use thin section of cell
- Add a stain
- Place a cover slip ontop of sample
How are electron microscopes better?
- higher magnification/resolution
- sample more visible
- sub-cellular structures more visible
How do you use a light microscope?
- place slide on stage and look through eyepiece lens
- turn focus wheel for a clear image
- Start with lowest objective lens magnification
- increase magnification and refocus
what is the function of plasmids in the bacteria?
- small rings of DNA
- code for extra genes alongside those provided by chromosomal DNA
how are egg cells adapted?
- special cell membrane
—> accepts one sperm and then becomes impermeable - cytoplasm
—> allows quick, repeated division - haploid nucleus
what adaptations do ciliated epithilial cells have?
- cilia
—> waft mucus down to stomach, where they are killed by stomach acid
what are some adaptations of root hair cells?
- large surface area
—> more water can move in by osmosis - mitochondria
—> provide energy for active transport of mineral ions
how would you use specimens with a light microscope?
- take a thin layer of cells
- add a small amount of a stain
- apply cells to your glass slide by placing them on
- lower a coverslip onto the slide
what is the independent variable in the pH and enzyme core practical?
the pH solutions
what is the dependant variable in the pH and enzyme core practical?
time taken for reaction to occur
what is the control variable in the pH and enzyme core practical?
- temperature
- volume of solutions used
what is the control experiment for the enzyme pH core practical?
same apparatus but tube set up without enzyme
what does amylase break down?
starch ——> simple sugars
what do proteases break down?
proteins ——> amino acids
what do lipases break down?
lipids (fats) ——> fatty acids
how would you test for reducing sugars?
- mix powdered food with** water**
- add benedict’s solution
- keep in hot water bath
- green = little sugar
- orange = more reducing sugars
- red = a lot of reducing sugars
how would you test for protein?
- mix powdered food with water
- add potassium hydroxide
- add two drops of copper sulfate
- will go from blue to purple
- more purple = more protein
how would you test for lipids?
- add ethanol to powdered food
- shake
- pour liquid into a test tube filled with water
- will go from clear to cloudy if lipids are present
how can you measure amount of energy in food using calomitery?
- put bunsen burner under cold water
- burn the food in the bunsen burner
- energy from food transferred to thermal energy
- change of temperature of water = amount of energy transferred
what is the equation to find energy per gram of food?
energy = mWater (g) * 4.2 * temp rise
————————————-
mass of food (g)
what is the independant variable in the calomitery experiement?
type of food
what is the dependant variable in the calomitery experiment?
energy released per gram of food
what are some control variables in the calorimitery experiment?
- volume of water
- distance between burning food and calorimeter
- point food is burned to
what is the independent variable in the osmosis practical?
concentration of sucrose solution
what is the dependant variable in the osmosis practical?
percentage change in mass of potato
what is the control variable in the osmosis practical?
- amount of moisture on outside of potato strips as they were dried
- time they were kept in solution for
- type of potato
