Cells Flashcards

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1
Q

describe the features of bacterial (prokaryotic) cells?

A
  • no nucleus- strand of DNA floats freely in the cytoplasm
  • one or more small rings of DNA (plasmids)
  • no chloroplasts or mitchondria
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2
Q

how big are cells (animal and plant)?

A

0.01-0.10mm

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3
Q

what structures do an algal cell include?

A
  • nucleus
  • chloroplast
  • mitochondria
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4
Q

how much is one order of magnitude?

A

10x

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5
Q

mitochondria function

A

where aerobic respiration takes place for energy

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6
Q

ribosome function

A

make proteins

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7
Q

permanent vacuole function

A

contains cell sap

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8
Q

chloroplast function

A

where photosynthesis occurs

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9
Q

name 4 specialised animal cells

A
  • neurone (nerve cell)
  • red blood cell
  • sperm cell
  • skeletal muscle cell
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10
Q

name 2 specialised plant cells

A
  • phloem cell
  • xylem cell
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11
Q

what is the difference between differentiation in animal cells and in plant cells?

A

animal cells lose ability to differentiate early on whereas most plant cells don’t ever lose the ability

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12
Q

define magnification

A

how much a lens can make an object seem larger

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13
Q

define resolution

A

the shortest distance between two points on a specimen that can still be seen as two different points

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14
Q

magnification formula

A

magnification= size of image/ size of real object

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15
Q

how do bacteria reproduce?

A

they replicate (double) around every 20 minutes by binary fission (form of cell division)

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16
Q

what conditions are required for bacteria to reproduce?

A
  • moisture
  • warmth
  • acidity
  • protein/food
  • time
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17
Q

describe how to prepare an uncontaminated culture

A
  • in a nutrient broth solution providing hte bacteria with all the nutrients they need
  • or by spreading onto agar plates (hot molten agar on sterile petri dishes) to form individual colonies
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18
Q

formula for finding cross-sectional area of colonies or clear areas around colonies

A

πr²

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19
Q

calculating number of bacteria in a population after certain time (given mean division time) (20 minutes)

A
  • minutes/ 20= number of divisions
  • bacteria at beginning of growth period x 2 to the power of the number of divisions
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20
Q

describe how genetic information is stored in the nucleus of a cell

A

cells contain a nucleus which contains choromosones which are made of DNA (genetic information) and proteins which contain genetic code

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21
Q

name and describe the first process in the cell cycle

A
  • growth and DNA replication
  • cell grows/ increases amount of subcellular structures then replicates DNA to form 2 copies of each chromosone
22
Q

name and describe the second process of the cell cycle

A
  • mitosis
  • chromosones line up in centre of cell
  • one set of chromosones is pulled to eachend of cell
  • nucleus divides
  • cytoplasm and cell membrane divide forming 2 identical daughter cells
23
Q

sources of stem cells in animals

A
  • bone marrow
  • blood
  • brain
24
Q

sources of stem cells in plants

A

meristems at tips of their rootd and shoots

25
Q

describe the use of stem cells in the production of plant clones

A
  • throughout the plant’s life, it’s meristem cells cam differentiate into sny type of plant cell
  • quick and cheap for making plant clones
  • can stop rare species being wiped out
26
Q

describe the use of animal stem cells in therapuetic cloning

A
  • e.g. can use someone’s DNA to clone one of their organs for a transplsnt
  • makes plant clones quick and cheap
  • the cells are stimulated to divide and they turn into an embryo so cells remove acid used
27
Q

benefits of using stem cells in production of plant clones and therapeutic cloning

A
  • can treat diseases such as type 1 diabetes, sclerosis, spine and brain injury (which can lead to paralysis)
  • used for medicine and research
  • can stop rare species of plants dying out
28
Q

risks of using stem cells in production of plant clones and therapeutic cloning

A
  • cultured stem cells could get viruses and pass them on to a patient
  • some mutated stem cells have been observed to behave like cancer cells
29
Q

issues of using stem cells in production of plant clones and therapeutic cloning

A
  • clinical- no guarantee of success, hard to find suitable donors, hard to store
  • ethical- some people think embryos are potential lives and it is wrong to use them for research (IVF- in vitro fertilisation)
  • social- educating, wether benefits outweigh risks, patients could get false hope since stem cell therapies are still in developmental stages
30
Q

what is diffusion?

A

spreading out of particles from an areas of higher concentration to an area of lower concentration

31
Q

2 examples of diffusion

A
  • in a leaf- oxygen moves out of a cell by diffusion and carbon dioxide moves in by diffusion
  • in lungs- carbon dioxide diffuses from an area of high concentration of carbon dioxidein the blood to low concentration in the alveolus and oxygen diffuses from high concentration of oxygen in the alveolus to low concentration in the blood
32
Q

what are the 3 factors that affect diffusion

A
  • greater concentration gradient (difference in concentration)= faster rate of diffusion
  • higher temperature= faster rate of diffusion (particles have more energy)
  • greater surface area of the membrane seperating the regions= faster rate of diffusion
33
Q

how does surface area to volume ratio relate to single-celled and multicellular organisms?

A

as surface area and volume (and general size) of an organism increases, the surface area to volume ratio decreases

34
Q

formula for surface area to volume ratio

A

surface area/ volume

35
Q

what 4 factors increase the effectiveness of an exchange surface?

A
  • thin membrane- reduces diffusion distance
  • blood supply- maintains high concentration gradient
  • large surface area- allows more of the substance to diffuse at the same time
  • ventilation- maintains a high concentration gradient
36
Q

what adaptions do the exchange surfaces small intestines, lungs, gills, roots and leaves have to increase their effectiveness

A
  • small intestines- large surface area due to villi and a constant blood supply
  • lungs- large surface area due to alveoli and thin walls
  • gills- large surface area due to blood capillaries and thin walls
  • roots- large surface area
  • leaves- large surface area
37
Q

what is osmosis?

A

movement of water molecules across a partially permeable membrane from an area of higher water concentration to an area of lower water concentration

38
Q

how do you calculate water uptake?

A

record the time taken for a bubble in the potometer (tube) to move a set distance.
on a graph, this wiuld be the gradient (change in y/ change in x)

39
Q

formula for percentage gain and loss of mass of plant tissue

A

[(new mass - original mass= change in mass) / original mass] x 100

40
Q

what is active transport?

A

movement of dissolved molecules across a partially permeable membrane (in or out of a cell) from a region of lower concentration to an area of higher concentration (against concentration gradient)

41
Q

2 examples of active transport

A
  • sugar molecules needed for respiration are absorbed from the gut
  • root hairs absorb minerals in plants for healthy growth
42
Q

differences between diffsuio, osmosis and active transport

A
  • in diffusion, substances move from a high concentration to low concentration whereas in osmosis it is the movement of water and in active transport, substances move against the concentration gradient
  • diffusion and osmosis don’t require energy whereas active transport does
43
Q

what is the multiple of the unit of the prefix tera (T)?

A

10¹²

44
Q

what is the multiple of the unit of the prefix giga (G)?

A

10⁹

45
Q

what is the multiple of the unit of the prefix mega (M)?

A

1 000 000 (10⁶)

46
Q

what is the multiple of the unit of the prefix kilo (k)?

A

1000

47
Q

what is the multiple of the unit of the prefix deci (d)?

A

0.1

48
Q

what is the multiple of the unit of the prefix centi

A

0.01

49
Q

what is the multiple of the unit of the prefix milli (m)

A

0.001

50
Q

what is the multiple of the unit of the prefix micro (µ)?

A

0.000001 (10⁻⁶)

51
Q

what is the multiple of the unit of the prefix nano (n)?

A

10⁻⁹