topic 1- key concepts in bio Flashcards

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1
Q

Difference between Eukaryotes and Prokaryotes

A
  • eukaryotic cells are complex and include animal and plant cells
  • prokaryotic cells are smaller and simpler e.g bacteria ( they’re single celled organisms)
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2
Q

What is found in Eukaryotic cells ( animal and plant)

A

Animal and plant cells
- Nucleus ( contains genetic information– DNA– of the cell and controls activities of cell)
- Cytoplasm (liquid substance in which chemical reactions occur and contains enzymes)
- Cell membrane (controls what enters and leaves the cell)
- Mitochondria (where aerobic respiration takes place - provides energy for a cell)
-Ribosomes ( Where protein synthesis occurs)
ONLY IN PLANT CELLS
- chloroplast ( Where photosynthesis takes place and contains chlorophyll that harvests light needed for photosynthesis)
- Permanent Vacuole ( contains cell sap, improves rigidity)
-Cell wall ( made from cellulose and strengthens cell

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3
Q

What is found in bacterial cells

A
  • Cytoplasm
  • Cell membrane
  • Cell wall
  • Chromosomal DNA ( bacterial cells have no nucleus- floats in cytoplasm)
  • Plasmid ( small rings of DNA and code for extra genes)
  • Flagellum ( Long, thin tails attached to bacteria that allows them to move)
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4
Q

What is a specialised cell?

A
  • cell gaining new sub-cellular structures to be suited to its role
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5
Q

How sperm cell is specialised ?

A

-carry male’s DNA to the egg for reproduction
-Streamlined head and long tail to aid swimming
-Many mitochondria to supply energy to
allow cell to move

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6
Q

How egg cell is specialised ?

A
  • specialised to accept single sperm cell and develop into embryo
  • lots of mitochondria to provide energy source for developing embryo
  • Large size and cytoplasm to allow quick, repeated division as embryo grows
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7
Q

How root cell is specialised ?

A
  • have large surface area due to root hairs, meaning more water can move in
  • large permanent vacuole affects the speed of movement of water from soil to the cell
  • mitochondria provide energy from respiration for active transport of mineral ions into the root hair cell
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8
Q

How phloem cell is specialised ?

A
  • Cell walls of each cell form structures called sieve plates when they break down, allows movement of substances from cell to cell
  • lose many sub-cellular structures, energy cells need to be alive is supplied by mitochondria of the companion cells.
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9
Q

What are the two main types of microscopes ?

A

-light and electron

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10
Q

Magnification equation

A

magnification = image size/ actual size

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11
Q

Converting from milli, micro, nano and picometers

A

Milli x10^-3 divide by 1000 to get micrometers and etc.
Micro x10^-6
Nano x 10^-9
Pico x 10^-12

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12
Q

What is an enzyme ?

A
  • biological catalyst speeds up rate of reaction
  • fit in lock and key method– active site and substrate are complimentary
  • form enzyme-substrate complex
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13
Q

What happens to an enzyme when it exceeds its optimum temp. ?

A

-becomes too hot bonds that hold enzyme together will break.
changes the shape of the active site, so the substrate can no longer ‘fit into’ the enzyme.
- denatured

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14
Q

What happens to an enzyme when pH is too high or low?

A
  • forces that hold amino acid chains that make up the protein will be affected.
    -change shape of active site, substrate can no longer
    fit in.
  • denatured
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15
Q

Practical- when starch is present

A
  • Place drop of iodine solution on each well of a tray.
  • Label test tube with pH to be tested. Place in water beaker w/ 50ml water place above Bunsen Burner for 3 minutes.
    3. 2cm3 amylase solution, 2cm3 starch solution and 1cm3 of buffer pH solution in test tube and start stopwatch.
  • After 10 seconds, use pipette to place a drop the solution into one well containing iodine solution if mixture turns blue-black starch is present & hasn’t yet been broken down.
  • Repeat Step 4 after another 10 seconds, repeat until solution remains orange –record time taken
    • control conc. and vol. of amylase solution
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16
Q

use of enzymes in carbohydrase, proteases and lipase

A

carbohydrase– convert carbohydrate to simple sugar
proteases – convert proteins to amino acids
lipase– convert lipids( fats ) to fatty acids & glycerol

17
Q

How to test for reducing sugars ( Benedict’s solution )

A
  • Presence of reducing sugar indicated by colour

change to reddish-brown

18
Q

Test for protein (Biuret test)

A
  • add drops of potassium hydroxide (KOH) to make it alkali, then add copper (II) sulfate
  • observe colour change if protein is present blue to violet
19
Q

Test for lipids (Emulsion test)

A
  • add ethanol to food sample and shake then add water
  • If lipids present, will be indicated by formation of white emulsion layer at top of sample.
  • more white emulsion, the more lipids
20
Q

what 3 ways does transport occur?

A
  • osmosis
  • diffusion
  • active transport
21
Q

Why do we use Bunsen burner and water beaker in practical testing for starch

A
  • keep solution at relatively constant temperature throughout reaction (temperature is a control variable in this experiment).
22
Q

Why does transport occur in and out of cells ?

A
  • carry substance like oxygen, glucose and waste products in and out to support life processes
23
Q

What is diffusion ?

A
  • net movement of particles from high concentration to low concentration
24
Q

Properties of diffusion

A
  • all particles possess Kinetic energy
  • random movement
  • passive process
25
Q

What is osmosis?

A

Movement of water particles from a higher concentration to a low concentration through a partially permeable membrane

  • form of passive transport ( requires no energy)
26
Q

What is active transport?

A
  • requires energy

- move molecules against concentration gradient from low concentration to high concentration

27
Q

Osmosis potato practical

A

Cut potato equal size

  • remove excess water.
  • Measure initial mass of potatoes
  • put potatoes in sucrose solutions w/ different concentrations
  • clean w/ tissue paper again & record new mass.
  • Find difference in mass & calculate percentage gain or loss of mass
28
Q

What are independent, dependant & control variable in Osmosis potato experiment

A

Independent variable:
-Conc. of sucrose solution

Dependant variable:
- measuring change of mass in potatoes

Control variable:
- potato size