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BIOLOGY > SB1 - KEY CONCEPTS IN BIOLOGY > Flashcards

SB1 - KEY CONCEPTS IN BIOLOGY Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

all living organisms can be grouped of ‘classified’ using the classification system that consists of five kingdoms. these five kingdoms are:

A
  • animals
  • plants
  • fungi
  • protoctists
  • prokaryotes
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2
Q

kingdoms containing eukaryotic organisms (4)

A
  • animals
  • plants
  • fungi
  • protoctists
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3
Q

features of eukaryotes (2)

A
  • can be multicellular or single-celled
  • made up of cells that contain a nucleus bound by a distinct membrane
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4
Q

features of prokaryotes (3)

A
  • always single-celled
  • do not contain a nucleus (instead, the nuclear material is found in the cytoplasm)
  • prokaryotic cells are substantially smaller than eukaryotic cells
    bacteria are prokaryotic organisms
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5
Q

main features of animals (8)

A
  • multicellular
  • cells contain a nucleus with a distinct membrane
  • cells do NOT have cellulose cell walls
  • cells do NOT contain chloroplasts (so unable to carry out photosynthesis)
  • feed on organic substances made by other living things
  • often store carbohydrates as glycogen
  • usually have nervous coordination
  • able to move from place to place
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6
Q

cell structures found in animal cells (5)

A
  • nucleus
  • cytoplasm
  • cell membrane
  • ribosomes
  • mitochondria
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7
Q

function of the nucleus

A
  • contains the genetic material (DNA) which controls the activities of the cell
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8
Q

function of cytoplasm

A
  • a gel-like substance composed of water and dissolved solutes
  • supports internal cell structures
  • site of many chemical reactions, including anaerobic respiration
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9
Q

function of cell membrane

A
  • holds the cell together, separating the inside of the cell from the outside
  • controls which substance can enter and leave the cell
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10
Q

function of ribosomes

A
  • found in the cytoplasm
  • site of protein synthesis
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11
Q

function of mitochondria

A
  • site of most of the reactions involved in aerobic respiration, where energy is released to fuel cellular processes
    ** energy is RELEASED not made **
  • cells with high rates of metabolism (carrying out many different cell reactions) have significantly higher number of mitochondria than cells with fewer reactions taking place
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12
Q

main features of plants (7)

A
  • multicellular
  • cells contain a nucleus with a distinct membrane
  • cells have cell walls made out of cellulose
  • cells contain chloroplasts (so they can carry out photosynthesis)
  • they feed by photosynthesis
  • store carbohydrates as starch or sucrose
  • do not have nervous coordination
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13
Q

cell structures found in plant cells (8)

A
  • nucleus
  • cytoplasm
  • cell membrane
  • ribosomes
  • mitochondria
    +
  • cell wall
  • chloroplasts
  • permanent vacuole
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14
Q

function of cell wall

A
  • made of cellulose (a polymer of glucose)
  • gives the cell extra support, defining its shape
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15
Q

function of chloroplasts

A
  • contains green chlorophyll pigments (to absorb light energy) and the enzymes needed for photosynthesis
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16
Q

function of permanent vacuole

A
  • contains cell sap; a solution of sugars and salts dissolved in water
  • used for storage of certain materials
  • also helps support the shape of the cell
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17
Q

main features of fungi (9)

A
  • usually multicellular but some (eg. yeast) are single-celled
  • multicellular fungi are mainly made up of thread-like structures known as hyphae that contain many nuclei and are organised into a network known as a mycelium
  • cells contain a nucleus bound by a distinct membrane
  • cells have cell walls made of chitin
  • cells do not contain chloroplasts (so cannot carry out photosynthesis)
  • feed by secreting extracellular digestive enzymes onto the food (usually decaying organic matter) then absorbing the digested molecules
  • some fungi are parasitic and feed on living material
  • some fungi store carbohydrates as glycogen
  • do not hav coordination
    examples of fungi include: moulds, mushrooms, yeasts
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18
Q

cell structures found in fungi (6)

A
  • nucleus
  • cytoplasm
  • cell membrane
  • ribosomes
  • mitochondria
    +
  • cell wall (containing chitin, not cellulose)
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19
Q

main features of protoctists (7)

A
  • a very diverse kingdom of organisms that don’t really belong in any of the other eukaryotic kingdoms
  • mainly microscopic and single-celled but some aggregate (group together) into larger forms
  • cells contain a nucleus bound by a distinct membrane
  • some have features making them more like animal cells, some have features making them more like plant cells
  • some protoctists photosynthesis, some feed on organic substances made by other living things
  • do not have nervous coordination
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20
Q

cell structures found in protoctists

A
  • nucleus
  • cytoplasm
  • cell membrane
  • ribosomes
  • mitochondria
    +
  • food vacuole
  • contractile vacuole
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21
Q

the nuclear material of prokaryotic cells is found in the _________

A

cytoplasm

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22
Q

prokaryotes are too small to contain __________ or ____________

A

chloroplasts or mitochondria

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23
Q

bacteria are (prokaryotic/eukaryotic) organisms

A

prokaryotic

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24
Q

features of bacteria (6)

A
  • microscopic single-called organisms
  • possess a cell wall (made of peptidoglycan, not cellulose), cell membrane, cytoplasm and ribosomes
  • lack a nucleus but contain a circular chromosome of DNA that floats in the cytoplasm
  • plasmids are present in prokaryotes; small rings of DNA (also floating in the cytoplasm) that contain extra genes to those found in the chromosomal DNA
  • lack mitochondria, chloroplasts and other membrane-bound organelles found in eukaryotic cells
  • some bacteria also have a flagellum or several flagella; long, thin, whip-like tails that allow them to move
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25
Q

specialised cells definition

A

cells that have developed certain characteristics (adaptations) in order to perform particular functions

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26
Q

cells specialise by undergoing _______________

A

differentiation

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27
Q

describe what happens during differentiation

A

a process where cells develop the structure and characteristics needed to be able to carry out their functions

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28
Q

examples of specialised cells in animals (3)

A
  • sperm cells
  • egg cells
  • ciliated epithelial cells
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29
Q

function of a sperm cell

A

reproduction: to carry the DNA of the male to the egg cell (ovum) of the female

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30
Q

adaptations of a sperm cell (4)

A
  • head contains the genetic material for fertilisation in a haploid nucleus (containing half the normal number of chromosomes)
  • the acrosome in the head contains digestive enzymes so that a sperm can penetrate an egg
  • the mid-piece is packed with mitochondria to release energy needed to swim and fertilise the egg
  • the tail enables the sperm to swim
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31
Q

function of an egg cell

A

reproduction: to be fertilised by a single sperm and develop into an embryo

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32
Q

adaptations of an egg cell (3)

A
  • contains a lot of cytoplasm which has nutrients for the growth of the early embryo
  • haploid nucleus contains half the genetic material for fertilisation
  • cell membrane changes after fertilisation by a single sperm so that no more sperm can enter
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33
Q

function of ciliated epithelial cells

A

wafting bacteria and other particles (trapped by mucus) up to the throat (to be coughed out) or down to the stomach (to be digested)

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34
Q

adaptations of a ciliated epithelial cell (1)

A
  • extensions of the cytoplasm at the surface of the cell form hair-like structures called cilia which beat to move mucus and trapped particles up to the throat
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35
Q

the first microscopes were discovered in the __th century

A

17th century

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36
Q

the first cells were observed by ______ _____ in 1665 using a _____ _________

A

Robert Hooke, light microscope

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37
Q

with a modern light microscope, it is possible to see images of _____

A

cells and large sub cellular structures (like nuclei and vacuoles)

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38
Q

______ are often required to highlight certain parts of cells when using a light microscope

A

stains

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39
Q

maximum magnification of light microscopes

A

approximately 1000-2000x

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40
Q

the first electron microscopes were developed in the 19__s

A

1930s

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41
Q

electron microscopes use ______ __ _________, rather than light, to visualise specimens

A

beams of electrons

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42
Q

electron microscopes have a (higher/lower) resolution and magnification than a light microscope

A

higher

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43
Q

with an electron microscope, it is possible to see images of _____

A

many more sub cellular structures such as mitochondria, chloroplasts and ribosomes

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44
Q

maximum magnification of an electron microscope

A

2,000,000x

45
Q

magnification formulas (2)

A

magnification = image size / actual size
magnification = magnification of eyepiece lens x magnification of objective lens

46
Q

components of a microscope

A
  • eyepiece lens (where you put your eye)
  • objective lens (closest to the specimen, have low/medium/high power)
  • stage (microscope slide is placed here)
  • light source (mirror underneath specimen)
  • coarse focus (focuses the low and medium power objective lenses) and fine focus (focuses the high power objective lens)
47
Q

commonly used stains

A
  • methylene blue to stain cheek cells
  • iodine to stain onion cells
48
Q

[microscopy] to prevent cells from being damaged by dehydration you can

A

add a drop of water to the specimen (beneath the coverslip)

49
Q

limitations of optical microscopes (3)

A
  • size of cells may appear inconsistent; cell structures are 3d and different tissue samples have been cut at different planes)
  • optical microscopes have lower magnification power than other types of microscopes; there are some structures that cannot be seen
  • treatment of specimens when preparing slides could alter the structure of cells
50
Q

1m = _mm

A

1m = 1000mm

51
Q

1mm = _μm

A

1mm = 1000μm

52
Q

1μm = _nm

A

1μm = 1000nm

53
Q

enzymes are _______

A
  • proteins that act as biological catalysts to speed up the rate of a chemical reaction without being changed or used up
  • they are made in living cells
  • enzymes are necessary to all living organisms as they allow all metabolic reactions to occur at a rate that can sustain life
54
Q

enzymes are ________ to one particular substrate

A

specific

55
Q

the active site of the enzyme is where _______

A

the substrate attaches

56
Q

active sites are a _____________ shape to the substrate

A

complementary

57
Q

steps of an enzyme catalysed reaction

A
  1. enzyme and substrates randomly move about in solution
  2. when an enzyme and its complementary substrate randomly collide, an enzyme-substrate complex forms and the reaction occurs
  3. a product forms from the substrate and is then released from the active site. the enzyme is unchanged and will go on to catalyse further reactions
58
Q

if the bonds that hold the enzyme together are disrupted or broken the enzyme is _________

A

denatured; the active site loses its shape

59
Q

enzyme denaturation is (reversible/irreversible)

A

irreversible; once enzymes are denatured they cannot regain their proper shape and the reaction they are catalysing will stop

60
Q

conditions that cause enzymes to denature (2)

A
  • high temperatures
  • extremes of pH
61
Q

enzymes work fastest at their _______ temperature

A

optimum

62
Q

in the human body, the optimum temperature is about __°C

A

37°C

63
Q

low temperatures (do/do not) denature enzymes

A

low temperatures do not denature enzymes
- they just make them work more slowly due to a lack of kinetic energy

64
Q

as temperature increases (towards the optimum), activity of enzymes _________

A

increases (more kinetic energy -> more collisions)

65
Q

as temperature increases (beyond the optimum), enzymes ________

A

denature

66
Q

factors affecting enzyme action (3)

A
  • temperature
  • pH
  • substrate concentration
67
Q

as substrate concentration increases, activity of enzymes _________

A
  • increases to a point; likelihood of enzyme-substrate complex formation increases
  • however all available active sites eventually become saturated and enzyme activity will PLATEAU
68
Q

rate of reaction formula

A

rate = change / time
OR
rate = amount of substrates used or product formed / time

69
Q

rate of reaction formula IF not told how much something has changed

A

rate = 1 / time

70
Q

the purpose of digestion is _______

A

to break down large, insoluble food molecules into smaller, soluble molecules that can be absorbed into the bloodstream

71
Q

carbohydrases are a group of enzymes that break down ______ into _______

A

carbohydrates -> simple sugars eg. glucose

72
Q

example of a carbohydrase (1)

A

amylase

73
Q

amylase is made in the _______ (3)

A
  • salivary glands
  • pancreas
  • small intestine
74
Q

amylase breaks down ______ into _______

A

starch -> glucose

75
Q

proteases are a group of enzymes that break down ________ into _____ _____

A

proteins -> amino acids

76
Q

example of a protease (1)

A

pepsin

77
Q

pepsin is made in the _______ (1)

A

stomach

78
Q

lipases are enzymes that break down ______ to ________ and _____ _____

A

lipids (fats) -> glycerol and fatty acids

79
Q

lipase enzymes are produced in the ________ and secreted into the _____ _________

A

pancreas, secreted into small intestine

80
Q

carbohydrates are synthesised by joining ______ ______ together

A

simple sugars

81
Q

proteins are synthesised by joining _____ _____ together

A

amino acids

82
Q

lipids are synthesised by joining _____ _____ or ________

A

fatty acids or glycerol

83
Q

describe the food test for glucose/reducing sugars

A
  • add benedict’s solution to the sample solution in a test tube
  • heat in a boiling water bath for 5 minutes
  • a positive test will show a colour change from blue -> orange or brick red
84
Q

describe the food test for starch

A
  • add drops of iodine solution to the food sample
  • a positive test will show a colour change from orange-brown -> blue-black
85
Q

describe the food test for protein

A
  • add drops of biuret solution to the food sample
  • a positive test will show a colour change from blue -> violet/purple
86
Q

describe the food test for lipids

A
  • mix the food sample with ethanol and shake
  • allow time for the sample to dissolve in the ethanol
  • strain the ethanol solution into another test tube
  • add the ethanol solution to an equal volume of cold distilled water
  • a positive test will show a cloudy emulsion forming
87
Q

describe a simple calorimetry experiment

A
  • pour water into a boiling tube and record it’s starting temperature
  • weigh the initial mass of the food sample
  • set fire to the sample of food using a bunsen burner and hold the sample 2cm from the boiling tube u tik it has completely burned
  • record the final temperature of the water
  • weigh the mass of any remaining food
88
Q

limitations of a calorimetry experiment

A
  • incomplete burning of the food sample
  • heat energy is lost to the surroundings
89
Q

ways for substances to move in and out of cells (3)

A
  • diffusion
  • osmosis
  • active transport
90
Q

diffusion is ______

A
  • the movement of molecules from a region of higher concentration to a region of lower concentration
  • molecules move down a concentration gradient
91
Q

in diffusion, molecules move (up/down) a concentration gradient

A

down

92
Q

describe cell membrane permeability

A

partially permeable:
smaller molecules can diffuse across the membrane but larger molecules cannot

93
Q

examples of diffusion in living organisms (6)

A
  • small intestine: digested food products diffuse from small intestine to blood
  • leaf: oxygen diffuses from air spaces between mesophyll cells to mitochondria in all cells
  • leaf: carbon dioxide diffuses from air spaces between mesophyll cells to chloroplasts in mesophyll cells
  • leaf: water vapour diffuses from stomata to air outside stomata
  • lungs: oxygen diffuses from alveolar air space to blood in capillaries around alveoli
  • lungs: carbon dioxide diffuses from blood in capillaries around alveoli to alveolar air space
94
Q

factors that influence diffusion

A
  • surface area : volume ratio
  • diffusion distance
  • temperature
  • concentration gradient
95
Q

diffusion is a form of (active/passive) transport

A

PASSIVE transport

96
Q

osmosis definition

A

the movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane

97
Q

osmosis is a form of (active/passive) transport

A

PASSIVE transport

98
Q

water can move in and out of cells by _______

A

osmosis

99
Q

osmosis occurs (up/down) a concentration gradient

A

down

100
Q

a concentrated solution has a ___ water potential

A

low

101
Q

a dilute solution has a ____ water potential

A

high

102
Q

describe red blood cells in a hypertonic solution

A
  • red blood cells have HIGHER water potential than solution
  • water moves out of cells
  • cells shrivel up
103
Q

describe red blood cells in an isotonic solution

A
  • water potential EQUAL between red blood cell and solution
  • no net movement of water
  • normal cells
104
Q

describe red blood cells in a hypotonic solution

A
  • red blood cells have LOWER water potential than solution
  • water moves into cells
  • cells swell, may lose (burst)
105
Q

why are plant cells protected from cell lysis?

A

they have a supporting cell wall whereas animal cells don’t

106
Q

percentage change in mass formula

A

(final mass-initial mass) / initial mass

107
Q

active transport definition

A

the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration

108
Q

energy is needed for active transport because ______

A

cells are moving against a concentration gradient, in the opposite direction from which they would naturally move (by diffusion)

109
Q

examples of active transport

A
  • allows glucose to be transported into the blood stream from the small intestine when the concentration of sugar molecules in the blood is higher
  • allows root hair cells in plants to move minerals such as magnesium ions from a region of lower concentration (the soil) to a region of higher concentration ( the cytoplasm of the cell)

BIOLOGY (6 decks)

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