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Biology > Biology Paper 1 > Flashcards

Biology Paper 1 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

How many sub-phases are there in interphase?

A

3

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2
Q

How do singles called organisms get rid of their waste?

A

It diffuses across the membrane

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3
Q

When, during the cell cycle, does semi-conservative replication happen?

A

S phase

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4
Q

Which phase of mitosis do chromosomes get pulled apart?

A

Anaphase

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5
Q

How does bacteria divide?

A

By binary fission

  • > circular loop of DNA replicates and move to opposite ends of cell
  • > plasmid replicates
  • > cytoplasm divides to form two daughter cells with each one having a single copy of circular DNA
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6
Q

What is binary fission?

A

Asexual reproduction of single cell organism eg bacteria

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7
Q

How many stages of mitosis?

A

4

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7
Q

What happens during G1 of interphase?

A

Organelles are made

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9
Q

Which stage of mitosis does chromosome condensing occur?

A

Prophase

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9
Q

What system within the body carries the waste around?

A

Circulatory

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11
Q

What is the First stage of mitosis?

A

Prophase

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12
Q

What do efficiency of gas exchange depend on? (3)

A

High surface area
Short diffusion pathway
High concentration gradient

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13
Q

How do insects carry out gas exchange?

A
  • Air enters through holes called spiracles
  • oxygen diffuses down the concentration gradient along the trachea
  • trachea are closely surrounded by cells
  • oxygen diffuses into cells
  • ventilations helps to maintain a high concentration gradient
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14
Q

How do insects prevent some water loss?

A
  • body covered in waxy cuticle that reduces evaporation

- insects can close their spiracles

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15
Q

How does a fish carry out gas exchange?

A
  • filaments and lamellae have a big surface area which increase efficiency of diffusion
  • thin epithelium means that there’s a short diffusion distance
  • countercurrent flow (of blood and water) maintains a high concentration gradient as water is always next to blood with a lower concentration of oxygen
  • circulation of blood replaces blood that is saturated with oxygen
  • Ventilation of water replaces water low in oxygen
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16
Q

What is the process of phagocytosis?

A

Engulfing of pathogens

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17
Q

Gases diffuse into leaves via what structure?

A

Stomata

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18
Q

What organ do insects use for gas exchange?

A

Tracheae

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19
Q

What is the main exchange surface in a leaf?

A

Mesophyll layer

20
Q

How does air enter the insect?

A

Via the spiracles

21
Q

What tissue is the diaphragm made from?

A

Muscle

22
Q

What genetic effect occurs when a small number of member of a population more to a new area?

A

Founder effect

23
Q

What causes genetic diversity within a species?

A

Alleles

24
Q

How many chromosomes does a haploid human cell contain?

A

23

25
Q

What impact does genetic bottleneck have on the genetic diversity of a population?

A

It decreases it

26
Q

What colour indicates a positive result in the bitter test?

A

Purple

27
Q

What makes a enzyme highly specific?

A

It’s tertiary protein structure

28
Q

What is the test for proteins known as?

A

Biuret test

29
Q

When starch and amylase are mixed in the presence of iodine solution, the blue-black colour rapidly disappears. This is due to the formation of which molecule?

A

Maltose

30
Q

What do you get when you hydrolyse starch?

A

Maltose

31
Q

*Differences between eukaryotic DNA and prokaryotic DNA

A

Prokaryotic DNA doesn’t have Histones

Prokaryotic cells have circular DNA whereas eukaryotic cells have double helix

32
Q

*When staining the chromosomes some parts of the chromosome have more stain than others causing them to appear striped. Suggest why

A

The dye stains regions of chromosomes that are rich in the base pairs Adenine (A) and Thymine (T) producing a dark band.

33
Q

*Define homologous chromosomes

A

A pair of matching chromosomes- each chromosome contains the same genes but may have different alleles

34
Q

*Define species richness

A

The number of different species in a community, a measure of biodiversity

35
Q

*Function of 2 enzyme involved in DNA replication

A

DNA polymerase- joins together nucleotides on a new strand of DNA
DNA helicase- breaks hydrogen bonds between two polynucleotides DNA strands

36
Q

*Why E-S complex increase rate of reaction

A

Lowers the activation energy so less energy needed to start reaction

37
Q

*How is lactose formed and how it forms a glycoprotein? (4 marks)

A
  • galactose
  • and glucose
  • condensation reaction
  • glycosidic bonds
  • Proteins modified in the Golgi apparatus and glycoprotein formed when a carbohydrate such as lactose is added to protein
38
Q

*Similarities and differences between the structures of Triglyceride and phospholipids

A

Similarities:
-both have glycerol
-both have fatty acids
- both store energy
Differences:
- phospholipids has a phosphate and 2 fatty acids but triglycerides has 3 fatty acids
- triglycerides are not water soluble but phospholipids are water soluble molecules

39
Q

*What is the structure of a amino acid?

A 
Variable group (R)
Amino group (H2N)
Carboxyl group (COOH)
Carbon atom 
Hydrogens atom
40
Q

Effect of exercise on ventilation

A

Increase tidal volume
Increase breathing rate
Increase pulmonary ventilation
Increase oxygen consumption

41
Q

Describe how a phagocyte destroys bacterium (5 marks)

A

In order

  1. ​Phagocytes attach themselves to the surface of the bacterium;
  2. ​Engulf the bacterium to form a vesicle / phagosome;
  3. ​Lysosomes move towards the vesicle and fuse with it;
  4. ​Hydrolytic enzymes / lysozymes break down / digest bacterium;
  5. ​Soluble products from the breakdown of the pathogen are absorbed into the cytoplasm of the phagocyte;
  6. ​Waste products leave the phagocyte by exocytosis / antigens from the bacteria are displayed on phagocyte cell membrane;
42
Q

Explain why T cells are effective against viruses (2 marks)

A

T cells destroy virus infected cells;

viruses need living cells to reproduce;

44
Q

Describe the principles and limitations of using a transmission electron microscope to investigate cell structure (5 marks)

A

Principles:
1. Electrons pass through / enter (thin) specimen;
2. Denser parts absorb more electrons;
3. (So) denser parts appear darker;
4. Electrons have short wavelength so give high resolution;
Principles: Allow maximum of 3 marks
5 max
Limitations:
5. Cannot look at living material / Must be in a vacuum;
6. Specimen must be (very) thin;
7. Artefacts present;
8. Complex staining method / complex / long preparation time;
9. Image not in 3D / only 2D images produced.

45
Q

Describe and explain how cell fractionation and ultracentrifugation can be used to isolate mitochondria from a suspension of animal cells (5 marks)

A

Any Five from:
1. Accept suitable method of breaking open cells.
2. Filter to remove (large) debris / whole cells;
2. Reject removes cell walls.
3. Use isotonic solution to prevent damage to mitochondria / organelles;
3. Ignore to prevent damage to cells.
4. Keep cold to prevent / reduce damage by enzymes / use buffer to prevent protein / enzyme denaturation;
5. Centrifuge (at lower speed / 1000 g) to separate nuclei / cell fragments / heavy organelles; 5. Ignore incorrect numerical values.
6. Re-spin (supernatant / after nuclei / pellet removed) at higher speed to get mitochondria in pellet / at bottom.
M2.(a) Any
1. Cell homogenisation to break open cells;
6. Must have location
Reject ref to plant cell organelles only once

46
Q

From a sample of epithelial cells, explain why some cells had twice the amount of dna than others

A

As the ones with twice the amount of dna were in late interphase and the other ones were in early interphase/dna had not replicated yet

Biology (14 decks)

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