Topic 1 - Key Concepts in Biology Flashcards Preview

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Flashcards in Topic 1 - Key Concepts in Biology Deck (37)
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1
Q

What is an electron microscope?

A

They use electrons rather than light to produce higher magnification and resolution than light microscope. Allowed to understand better how cells and subcellular structures work.

2
Q

What is meant by instruments resolution?

A

How well a microscope distinguishes between two points that are close together.

3
Q

How can cell structures (some) only be seen with an electron microscope but not light microscope?

A

Due to electron microscopes having a higher resolution than light microscopes, it allows us to see greater details of internal structure of mitochondria and chloroplasts.

4
Q

What is the magnification formula? (Total magnification)

A

Eyepiece lens magnification x objective lens magnification.

5
Q

What is magnification formula including sizes?

A

Image size / real size

6
Q

What is the order of units starting with millimetre and how do we reach next level down?

A

Millimetre x 1000 micrometre x nanometre x 1000 picometre multiply to go down / to go up

7
Q

Name parts in a plant cell

A

Cell wall, large permanent vacuole, chloroplasts, mitochondria, nucleus, ribosomes, cytoplasm, cell membrane.

8
Q

Name parts of animal cells

A

Cell membrane, nucleus, ribosomes, cytoplasm, mitochondria

9
Q

Recall the purposes of sub-cellular structures of: Nucleus

A

Contains genetic material

10
Q

Recall the purposes of sub-cellular structures of: Cytoplasm

A

Where chemical reactions take place

11
Q

Recall the purposes of sub-cellular structures of: Vacuole

A

Weak solution of sugar and salts and keeps internal structure

12
Q

Recall the purposes of sub-cellular structures of: Ribosomes

A

Translation of genetic material in synthesis of proteins

13
Q

Recall the purposes of sub-cellular structures of: Mitochondria

A

Reactions for respiration take place

14
Q

How are sperm cells adapted for their function?

A
  • Lots of mitchondria to provide energy for respiration needed to swim the distance
  • Has an acrosome at front of head where enzymes are stroed to break through membrane of the egg cell
  • Haploid nucleus
  • Tail/flagellum to swim to egg
15
Q

How are egg cells adapted to their function?

A
  • Nutrients in cytoplasm feed the embryo
  • Haploid nucleus
  • after fertilisation, membrane changes structure to stop any more sperm getting in so embryo has right amount of DNA
16
Q

How are ciliated epitherial cells adapted for their function?

A
  • Cilla hair-like structures on surface to move substances in one direction along survace (like mucus)
  • Large surface area to take in nutrients
  • Hairs stop mucus getting into lungs
17
Q

What are the common parts of a bacteria cell?

A

Flagellum to power along away from harmful toxins and towards nutrients and oxygen. Ribosomes, cell membrane, chromosomal DNA, PLasmid DNA for replication (small loops of extra DNA contains genes for drug resistance)

18
Q

Why are bacteria prokoryotic?

A

Because it has no nucleus

19
Q

What’s the difference between prokoryotic and eukoryotic cells?

A

Eukoryotic cells have a nucleus, prokoryotic are single celled organisms

20
Q

What are enzymes?

A

Proteins made from amino acids. It is a biological catalyst.

21
Q

What are the substrate concentrations of: Carbohydrates?

A

(Carbohydrases) carbohydrates to simple sugars amalyase

22
Q

What are the substrate concentrations of: Proteins?

A

(Proteases used) amino acids

23
Q

What are the substrate concentrations of: Lipids?

A

(Lipases) glycerol and fatty acids

24
Q

What does an enzyme do?

A

Break down large molecules by speeding up the rate of a reaction for growth and life processes

25
Q

How do we test for starch (a carbohydrate) in food?

A

Iodine test: positive = black, negative = brown/red

26
Q

How can we test for sugars in food?

A

Benedict reagent: positive = brick red ranges to negative = blue (take sample and add to hot water bath 75ºC

27
Q

How can we test for proteins in food?

A
  • Biuret Test is used for proteins, first add potassium hydroxide to make it alkaline then add copper sulfate solution (blue)
  • If no protein it stays blue (negative)
  • If there is it turns purple (positive)
28
Q

How can we test for lipids?

A

Emulsion test - Take sample and shake to mix with ethanol for a minute so it dissolved then pour into water

  • Positive = milky emulsion (precipitate)
  • Negative = clear
29
Q

How can we use calorimetry to measure the energy in food?

A
  • First get food sample which burns easily (dry)
  • Weigh the food and skewer it on a needle and hold under boiling tube
  • Add set volume of water to boiling tube and measure initial temperature of water
  • Set fire to food sample and heat boiling tube with it until burnt out
  • Measure water again and use formula:
    Energy in food (J) = Mass of water x temp change x 4.2
30
Q

What does enzyme specificity mean?

A

Enzymes only work with one substrate which they have a high specificity for. The substrate is the molecules changed in a reaction

31
Q

What is an active site? (Explain the role)

A

Every enzyme has an active site where the substrate joins it to catalyse the reaction. The substrate has to fit into the active site and if it doesn’t fit, the reaction wont be catalysed. This is called a lock and key mechanism.

32
Q

How can an enzyme become denatured?

A

An enzyme can be denatured if the temperature is too high (above 40ºC) or pH is too high or low. This is usually pH7 (neutral) but some enzymes are optimum at pH2 (acidic conditions).

33
Q

What is the effect of substrate concentration on enzymes?

A

The higher the substrate concentration, the faster the reaction as more likely enzyme will meet with substrate molecules. This is only up to a point as after certain point, all active sites are full so forms a plateau.

34
Q

What is the formula for enzyme activity?

A

Rate = 1000 / time

35
Q

What are the 3 processes which transport substances around an organism?

A
  • Diffusion - net movement of particles from an area of higher concentration to lower concentration (down concent. gradient)
  • Osmosis - net movement of water molecules across a partially permeable membrane from a region of high to low centration of water
  • Active transport - movement of particles across membrane for a low to high concentration using energy transferred during respiration (against concentration gradient).
36
Q

What is the effect of osmosis on cells and tissues?

A

Plant cells have rigid cell wall and when plant placed in hypotonic solution, it takes up water by osmosis and starts to swell but cell wall stops it bursting.

37
Q

How can we investigate osmosis with potatoes?

A
  • Get sucrose solution in ranging concentration from pure water to very concentrated sucrose
  • Use a potato corer to have evenly sized potato cores
  • Use mass balance to measure mass before then place into test tubes of different concentrations and leave for 40mins
  • Then remove and pat dry and measure mass again (for accuracy)
  • Then work out percentage change = difference mass / original x 100