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A-Level Biology🌼 > Breadth paper notes > Flashcards

Breadth paper notes Flashcards

1
Q

Role of epithelial cells

A

Epithelial cells - specialised for efficient food absorption - group together to form epithelial tissue in the small intestine

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2
Q

Role of goblet cells

A

Goblet cells - secrets mucus which trap pathogens

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3
Q

Purine bases

A

Purine bases: Adenine + Guanine
-Double ring structure

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4
Q

Pyrimidine bases

A

Pyrimidine bases: Thymine + Cytosine
-Single ring structure

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5
Q

Phosphorylation

A

Phosphorylation involves the addition of phosphate to an organic compound

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6
Q

Why do plants require specialised transport tissue?

A

Plants require a specialised transport tissue to overcome limitations of diffusion over large distances

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7
Q

When will a compound not be able to form hydrogen bonds?

A

Compounds with not OH group will not be able to form hydrogen bonds

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8
Q

What does non-overlapping and degenerate refer to for DNA?

A

-Non-overlapping: each nucleotide is only part of one triplet of bases
-Degenerate: more than one triplet codes for a specific amino acid

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9
Q

Where are endothelial cells found?

A

Endothelial cells are found in the lining of arteries, veins and capillaries

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10
Q

The role of cholesterol in cell surface membranes

A

Cholesterol binds to phospholipid fatty-acid tails, increasing the packing of the membrane, therefore reducing the fluidity of the membrane to make it less permeable/selectively permeable
-Cholesterol is temperature dependant = increasing temp decreases phospholipid mobility

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11
Q

Where is cholesterol found in cell surface membranes?

A

Cholesterol is found in the spaces among the hydrophobic tails of phospholipids in the lipid bilayer

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12
Q

Coenzymes

A

Coenzymes:
-Vitamin derived
-Organic cofactors
-Faciliates the binding of susbtrate to an enzyme
-Needed to allow the function of the enzyme

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13
Q

Why are plant root tips, eg onions, used to view cells undergoing mitosis?

A

Root tips are used to observe cells undergoing mitosis because:
-Site of cell division - meristematic tissue
-No chlorophyll or chloroplasts present

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14
Q

Stain used to highlight nuclei of cells

A

Methylene blue is a stain used to highlight nuclei of cells

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15
Q

Why do mammals store glycogen instead of glucose

A

Mammals store glycogen instead of glucose because:
–Glycogen is made up of branched alpha glucose molecules with 1,6 glycosidic bonds -> broken down fast for rapid release of glucose
-Insoluble - no effect on water potential
-Metabolically inacitve
-Stores lots of energy

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16
Q

Types of vesicles used by RER, types of vesicles used by Golgi

A

-RER: packages molecules into transport vesicles
-Golgi: packages molecules into secretory vesicles

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17
Q

How does the fluid mosaic model describe the structure of plasma membranes?

A

Fluid mosaic model:
-Phospholipids in the bilayer are free to move around eachother
-Hydrophobic tails face inwards, hydrophillic heads face outwards
-Proteins scattered/randomly arranged

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18
Q

Aquaporins

A

Aquaporins: Aquaporins are the water transporters. The diffusion of water across biological membranes is facilitated by special channel proteins called aquaporins. Aquaporins are designed to have hydrophilic pores which allow water molecules to move through them

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19
Q

How can water-soluble water molecules pass through the membrane?

A

Water-soluble molecules such as progesterone is hydrophobic, and so can dissolve in the phospholipid bilayer/is not repelled by the hydrophobic tails - this is done via aquaporins which act as water transporters

20
Q

What molecules make up ATP?

A

ATP is made up of phosphate groups, adenine and ribose

21
Q

When do you reject the null hypothesis?

A

The null hypothesis is rejected when the value is above the critical value - this is because the difference between the means is significant and not due to chance (and vice versa when its below critical value)

22
Q

Domains proposed by Carl Woese

A

Domains: Eukarya, (Eu)bacteria, Archae(bacteria)

23
Q

Cell component that appears in organisms of all three domains

A

Ribosomes appear in all three domains

24
Q

Ways of which scientists validate work

A

Scientist’s ways of validating works:
-Scientist conferences
-Replication of work

25
Q

How to calculate rate of reaction

A

1/Time

26
Q

What does SD show when data is spread out around mean?

A

Data spread out around mean - all data has small SD - little variation

27
Q

Details that must be followed to obtain valid results in the potato osmosis practical

A

Details that must be followed to obtain valid results in the potato osmosis practical:
-Discs the same size/surface area
-Same variety/part of the potato
-No skin on potatoes
-Remove excess water before (re)weighing
-Same number of discs placed in each sucrose solution

28
Q

How are two polynucleotide chains in a DNA molecule held together?

A

Polynucleotide chains are held together by:
-Phosphodiester bonds between nucleotides
-Hydrogen bonds between bases
-Purines and pyrimidine bases bonded together (A-T, C-G)

29
Q

Ways of which zoos can preserve species?

A

-Captive breeding programmes
-Education/awareness
-Support/promote conservation projects/research

30
Q

Why is oxygen not released until blood reaches capillaries?

A

Artery wall is too thick for oxygen to diffuse through

31
Q

Explain why blood loads-off more oxygen at actively respiring tissues

A

Why blood loads-off more oxygen at actively respiring tissues:
-Releases lots of carbon dioxide - decreases haemoglobin’s affinity for oxygen/increases the carbon dioxide affinity
-Lots of carbon dioxide -> dissociation of carbonic acid -> increases hydrogen ions -> release of more oxygen

32
Q

How mass flow of phloem sap occurs in plants with a vascular system

A

How mass flow of phloem sap occurs in plants with a vascular system:
1). Sucrose actively loaded into sieve tube element and reduces the water potential
2). Water follows by osmosis and increases the hydrostatic pressure in the sieve tube element
3). Water moves down sieve tube from higher hydrostatic pressure at source to lower hydrostatic pressure at sink
4). Sucrose is removed from sieve tube by surrounding cells and increases water potential inside sieve tube
5). Water therefore moves out the sieve tube and reduces the hydrostatic pressure

33
Q

Aorta component make-up (elastin, smooth muscle and collagen)

A

Aorta component make-up:
-Elastin 56%
-Smooth muscle 11%
-Collagen 33%

34
Q

Which part of the body contracts when we exhale?

A

When exhaling, the diaphragm contracts

35
Q

Why do zygotes undergo mitosis rather than meiosis?

A

Zygotes:
-Produces diploid cells with full sets of chromosomes -> for the zygote to grow
-Needs genetically identical cells (for growth and repair)

36
Q

Method of chromatography that will seperate amino acids in proteins such as collagen:

A

Method of chromatography that will seperate amino acids in proteins such as collagen:
1). Hydrolyse protein into amino acids
2). Place sample on chromatography paper (stationery phase)
3). Dry and repeat
4). Place paper in solvent

37
Q

Rough endoplasmic reticulum structure

A

Rough endoplasmic reticulum structure:
-Ribosomes attached on the outisde
-Phospholipid bilayer -> forms cisternae/network of membranes

38
Q

How are nucleotides in a DNA molecule arranged as two polynucleotide chains?

A

-Phosphodiester bonds between adjacent nucloetides
-Hydrogen bonds between complementary bases
-Polynucleotides arranged on antiparallel strand

39
Q

Role of the membrane in the rough endoplasmic reticulum

A

Role of the membrane in the rough endoplasmic reticulum:
-Compartmentalisation - maintains different conditions from cell cytoplasm
-Separating proteins that’s been/being synthesised from the rest of the cell
-Hold ribosomes/enzymes in place

40
Q

Protoctist features

A

Protoctist features:
-Unicellular or multicellular
-Contains a nucleus
-No cell wall
-Heterotrophic

41
Q

Antibody injection immunity type

A

Injection of antibodies is passive artificial immunity

42
Q

Bond type between glucose and fructose

A

1,6 glycosidic bonds

43
Q

Function of companion cells

A

Companion cells in the phloem function:
-Involved with ATP production for active processes, such as loading sucrose into sieve tubes

44
Q

Translocation definition

A

Translocation: transportation of assimilates in phloem between sources and sinks

45
Q

Translocation process( active loading and facilliated diffusion)

A

1). Sucrose enters phloem by active loading, where companion cells use ATP to transport hydrogen ions into surrounding tissue, creates gradient, allows H ions to diffuse back into companion cells
2).Facilitated diffusion involving co-transport proteins allows H ions to bring sucrose molecules into companion cells, causing sucrose conc to increase -> sucrose diffuses into sieve tube elements as a result

46
Q

Parenchyma tissue function

A

Parenchyma cells -> specialised for photosynthesis -> contain chlorophyll with chloroplasts

A-Level Biology🌼 (25 decks)

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