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biology > module 1: cells as the basis of life > Flashcards

module 1: cells as the basis of life Flashcards

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AP® Biology flashcards
1
Q

cell theory

A
  • all living organisms are composed of cells, they are unicellular or multicellular
  • cells are the basic unit of structure in all organisms
  • cells arise from pre-existing cells and cannot be created from non-living material
  • energy flow occurs within cells
  • heredity information (DNA) is passed on from cell to cell
  • all cells have the same basic chemical composition
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2
Q

calculating magnification

A
  • calculated by multiplying the magnification of the objective lens with the magnification of the ocular lens
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3
Q

calculating field of view

A
  • the higher the magnification, the smaller the field of view
  • using a microscope slide with graph paper
  • by moving the graph paper so that it lies across the diameter, you can measure the field of view for each magnification
  • using this field of view you can estimate size of objects being viewed under the microscope
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4
Q

micrometre

A
  • μm
  • x 1000 from mm
  • / 1000 to mm
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5
Q

microscopy

A

what distinguishes one cell from another

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6
Q

magnifying glass

A
  • simple microscope with one lens, distorts images at high magnifications
  • Leeuwenhoek (scientist)
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7
Q

compound microscope

A

uses more than one lens

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8
Q

sub stage light sources and condenses

A

help provide better light

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9
Q

iris diaphragm

A

increases depth of field (how much is in focus)

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10
Q

staining dyes

A

emphasize particular cell structures allowing better identification of cells and their parts

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11
Q

fluorescent dyes

A

also used with the light of or UV on, to show other structures or chemicals in cells

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12
Q

electron microscopes

A

have to use the specimen in a vacuum so it must be dead, the magnification is very high, there are two types of scanning

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13
Q

compute manipulations

A

used to create 3D images and add colour because electron images are only black and white

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14
Q

unicellular organisms

A
  • made of one cell
  • include bacteria, protozoa, unicellular algae and unicellular fungi or yeasts
  • oldest forms of life
  • prokaryotic or eukaryotic
  • single cell carries out all life processes - obtaining nutrients, exchanging gas, removing waste
    and reproduction
  • High SA:V ratio which allows for more efficient movement of substances
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15
Q

multicellular organisms

A
  • made of more than one cell, specialised cells
  • cells coordinate with each other to regulate functions of the body
  • different cells may be the nerve cells, skin cells, blood cells, bone cells
  • eukaryotic cells
  • large organisms made up of smaller cells increases SA:V ratio
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16
Q

prokaryotes (unicellular organisms)

A
  • smaller and simpler than eukaryotic cells
  • no membrane bound organelles
  • divided into archaea and bacteria
  • cell membrane
  • cytoplasm - where DNA resides
  • ribosome
  • genetic material
  • range of cell size: 0.1-5.0 μm
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17
Q

eukaryotes (uni and multicellular)

A
  • more complex and larger than prokaryotes
  • range of cell size: 10-100 μm
  • multicellular plants and animals are composed of a variety of different types of eukaryotic cells
  • plants, fungi, protist and animals
  • cell division by mitosis
  • has membrane bound organells
  • DNA found in membrane-bound nucleus
  • cell membrane
  • ribosomes
  • cytoplasm
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18
Q

cytoplasm function

A
  • serves as a surface for the organelles within the cell
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19
Q

nucleus function

A
  • storing the cell’s DNA (genetic material)
  • helps manage the cell’s activities
    - includes cell growth, reproduction, protein synthesis and metabolism
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20
Q

ribosomes function

A

responsible for making protein which is used to help manage chemical processes or repair damage to the cell

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21
Q

chloroplast function

A
  • photosynthesis occurs in this section of the cell
  • use the sunlight to convert the energy into sugars to power the plant cells
22
Q

golgi apparatus function

A

finishes, sorts, labels and ships proteins in vesicles

23
Q

lysosomes function

A
  • digest and remove waste from the cell
24
Q

mitochondria function

A
  • produce the energy for the cell (ATP) through cellular respiration
  • responsible for creating more than 90% of the energy needed to sustain life
  • help to digest nutrients
25
Q

cell wall function

A
  • made of cellulose
  • provides strength and security for the cell, this helps make branches, stems and leaves stronger
26
Q

cell membrane function

A
  • provides protection for the cell
  • provides a fixed environment inside the cell
  • regulates what goes in and out of the cell
27
Q

endoplasmic reticulum function

A

works on proteins (helps complete the proteins after ribosomes build them), makes membranes

28
Q

plant vacuole function

A

contained sacs of cells consisting of membranes housing inorganic or organic molecules, this includes enzymes that helps plants thrive

29
Q

cell membrane function

A
  • offer protection to the cell
  • regulate any substances as they enter or exit the organelles
30
Q

fluid mosaic model: cell membrane

A
  • membrane is extreme thin
  • controls the exchange of material between the internal and external environments of the cell
  • selectively permeable meaning only certain molecules are allowed in or out
  • permeable to small molecules and lipid-soluble molecules due to the phospholipids being made of lipids
  • involved in cell recognition and communication with other cells
31
Q

fluid mosaic model

A
  • cell membranes consist of a bilayer (two players) of phospholipid molecules
  • phospholipid molecules have a hydrophilic (water-attracting) ‘head’ and two hydrophobic (water-repelling) ‘tails’
  • hydrophilic heads form the outside and inside lining of the cell membrane, and the hydrophobic tails meet in the middle
  • other molecules, such as proteins: carbohydrates and cholesterol, are scattered throughout the bilayer
32
Q

membrane proteins

A

membrane proteins have various functions
- transporters
- enzymes
- cell surface receptors
- cell surface identity markers
- cell-to-cell adhesion proteins
- attachments to the cytoskeleton

33
Q

what is membrane permeability

A
  • permeability is the ability of a membrane to allow substances to pass through it
34
Q

what determines the movement of molecules across cell membranes

A
  • size: small molecules move fast
  • electrical charge: neutral molecules have high permeability but charged molecules do not
  • lipid solubility: molecules soluble in lipids move easily
35
Q

how do molecules move across cell membranes

A

movement of materials in and out of cells in either passive or active-
- passive movement requires no energy and occurs via diffusion of osmosis (high to low)

36
Q

diffusion

A
  • movement of any type of molecule from a high to low concentration
37
Q

simple diffusion

A
  • may involve movement solid, liquid or gas molecules through another medium of solid, liquid or gas
  • it is the process in which a substance moves through a semipermeable membrane or in a solution without any help from transport proteins
38
Q

facilitated diffusion

A
  • similar to simple diffusion
  • occur through transport proteins
  • movement of the molecules is assisted by carrier proteins or channel proteins
  • used by some larger molecules and electrically charged molecules
  • it is specific, passive and saturates when all carriers are occupied
39
Q

channel proteins

A
  • spans the cell membrane and allows direct passage from one side to the other
  • have open and closed states
40
Q

osmosis

A

a process by which molecules of water tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one

41
Q

isotonic solution

A
  • solute concentration inside = solute concentration outside
  • water molecules move in and out of cell freely cells stay normal
42
Q

hypotonic solution

A
  • solute concentration inside > solute concentration outside
  • water molecules move into the cell
  • cells swell
43
Q

hypertonic solution

A
  • solute concentration inside < solute concentration outside
  • water molecules move out of the cell
  • cells shrink
44
Q

enzyme

A
  • protein molecules that control all the chemical processes of living systems
  • produced within living cells
  • intracellular or extracellular
  • organic catalysts, also known as biological catalysts
  • responsible for increasing the rate of reactions that occur in living organisms, without enzymes metabolism would be so slow at body temp that insufficient energy would be available to maintain life
45
Q

catalysts

A
  • any substance that speeds up or brings about a chemical changes
  • remain unchanged at the end of a reaction
  • can be reused
46
Q

composition of enzymes

A
  • consist of long chains of amino acids that have been folded into a specific shape
  • each enzyme contains a specific active site and catalyses a distinct chemical reaction
  • the molecule on which an enzyme acts is called a substrate
  • the interaction occurs between the enzyme’s active site and the substrate, enzymes are substrate specific
47
Q

lock and key model

A

active site of the enzyme precisely matches the substrate, this interaction between the enzyme and the substrate explains why some enzymes are specialised for a given substrate

48
Q

induced fit model

A

substrate and the enzyme’s active site are not a precise fit, when exposed to a substrate the active site will experience a structural change and will enhance binding

49
Q

factors affecting enzymes

A
  • temperature, work best at around 37 degrees celsius
  • pH level, function within a working pH range of about pH 5-9 with neutral pH 7 being the optimum
  • if the conditions are not optimum the enzyme changes shape, altering the shape of the active site and substrates cannot bind to it (denaturing)
50
Q

photosynthesis stages

A
  • stage 1: light-dependent reactions
    • chlorophyll captures solar energy and uses it to produce adenosine triphosphate (ATP)
    • photolysis occurs (water splits into H and O2(g))
  • stage 2: light-independent reaction
    • don’t need light in this step
    • ATP from stage 1 provides energy
    • combine CO with H
    • produce glucose, water and ADP
    • takes place in the stroma
51
Q

aerobic respiration

A
  • chain of at least 20 separate reactions each catalysed by a specific enzyme

biology (4 decks)

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