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Biology Unit 1+2 > Unit 1: Chapter 1 + 2 > Flashcards

Unit 1: Chapter 1 + 2 Flashcards

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1
Q

Cells

A

Are the basic structural and functional units of life, all living organisms are built of one or more cells.

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2
Q

How big are cells?

A

Most cells are microscopic, only a few such as a human egg cell and amoeba can be seen with the naked eye.

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3
Q

Are viruses living or non-living?

A

Both, because of they;
don’t have a structure
cannot carry out metabolic activities
cannot self-replicate

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4
Q

Shape and functions

A

The size of the cells vary and therefore impacts on function

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5
Q

Motor neuron cells

A

Star-shaped
Have a long axon
Transmit nerve impulses from a person’s spinal cord to voluntary muscles

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6
Q

Smooth muscle cells

A

Contain proteins that crisscross the cell and when contracted they shorten
Found in the gut wall, walls of blood vessels and uterus
Can generate sustained involuntary contractions

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7
Q

Shapes of microbial cells

A

Rod-shaped
Corkscrew-shaped
Spherical

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8
Q

Are there fixed shapes for all cells?

A

No, some cells are able to move actively and therefore have a flexible plasma membrane

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9
Q

Cells capable of self-propelled movement

A

Cancer cells
White blood cells
Amoebas

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10
Q

Site of exchange

A

Plasma membrane - where materials are moved in and out of a cell to maintain essential functions

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11
Q

Rate of exchange

A

Must be quick enough that the materials are delivered fast enough but slow enough to avoid accumulation of waste materials

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12
Q

Surface area to volume ratio

A

Is the surface area of a plasma membrane available to supply material or remove wastes from the cytoplasm of a cell

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13
Q

Rules of SA: V ratio

A

As an object increases in size the SA: V ratio gets smaller
As an object decreases in size the SA: V ratio gets bigger
The higher the ratio the greater the efficiency of the exchange

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14
Q

Why are cells so small?

A

Beyond a given cell size, the 2-way exchange of materials across the plasma membrane cannot occur fast enough to sustain the volume of the cell contents

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15
Q

Prokaryote

A

Any cells or organisms without a membrane-bound nucleus (bacteria and archaea)
typically smaller (1-2 micrometres)
DNA is dispersed
Unicellular

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16
Q

Eukaryotes

A

Cell or organism with a membrane-bound nucleus (plants, animals, fungi)
typically larger (10-100 micrometres)
DNA stored as chromosomes in the nucleus
Unicellular/Multicellular

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17
Q

Similarities between eukaryotes and prokaryotes

A

Both have;

  • ribosomes
  • cell membrane
  • cytosol
  • vacuole
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18
Q

Cytoskeleton

A

3D networks of fine protein filaments and microtubules within the cell, to give it support and structure

  • determines cell chape
  • moves chromosomes during cell division
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19
Q

Organelles not enclosed in membranes

A

Ribosomes
Cilia and flagella
Centrioles

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20
Q

Animal cell organelles

A 
Nucleus
Mitochondria
Nuclear envolope
Nucleoulus
Ribosome
ER (smooth and rough)
Lysosome
Centriole
Protein microtubule
Golgi apparatus
Vesicle
Peroxisome
Endosome
Plasma membrane
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21
Q

Plant cell organelles

A 
Nucleus
Nucleolus
Mitochondria
Ribosomes
Endoplasmic reticulum
Plasma membrane
Cell wall
Microtubule
Vacuole
Chloroplast
Peroxisome
Vesicle
Golgi apparatus
Lysosome
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22
Q

Difference between animal and plant cell

A

Animals lack a cell wall, chloroplast and large central vacuole

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23
Q

Cell wall

A 
Plant cell
Outside cell membrane
Fully permeable
Provides strength and support to cells
Prevents over expansion of cells from osmosis
Made of cellulose
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24
Q

Cytosol

A

The fluid region in which the organelles exist

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25
Q

Which cells have secondary cell walls?

A

Woody plants and perennial grasses

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26
Q

Nucleus

A

Membrane bound organelle that controls the function of plant and animal cells

  • has a double membrane (nuclear envelope)
  • contains chromatin (DNA)
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27
Q

Nucleolus

A

Small part of the nucleus that makes ribosomes

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28
Q

Multinucleate

A

Many nucleus

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29
Q

Mitochondria

A

The site of cellular respiration
In animal and plant cells
Produces ATP for the cell to use as energy

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30
Q

Cellular respiration equation

A

O2 + C6H12O6 -> CO2 + H2O + ATP

Oxygen + Glucose -> Carbon dioxide + Water + Energy

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31
Q

Why would a cell need more mitochondria?

A

A cell that requires more energy ie; muscle cell

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32
Q

Ribosomes

A

Where amino acids are assembled to make proteins
In plant and animal cells
Attached to the Rough ER
Free floating

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33
Q

Rough endoplasmic reticulum

A

Organelle consisting of membrane-bound channels that transport substances within a cell with ribosomes attached to the outside

  • transports proteins within the cell
  • makes glycoproteins
  • folding proteins
  • assembling proteins (ribosomes)
  • plants and animals
34
Q

Smooth endoplasmic reticulum

A

Organelle consisting of membrane-bound channels that transport substances within a cell

  • synthesises and transports lipids
  • manufactures, detoxifies, stores and transports products
  • plants and animals
35
Q

Golgi complex

A

Organelle that packages material into vesicles for export from a cell

  • transported from Rough ER in transition vesicles
  • transported from Golgi body in secretory vesicles, merge with the plasma membrane and are excreted
  • plants and animals
36
Q

Lysosomes

A

A fluid-filled sac that contains digestive enzymes to break down excess macromolecules, old cell organelles and break down of substances
- animal and plant

37
Q

Peroxisomes

A

The organelle containing enzymes that detoxify various toxic materials that enter the bloodstream

  • oxidise fatty acids
  • break down long chain fatty acids
  • plants and animals
38
Q

Chloroplasts

A

Organelle that converts light into energy for the cell to use

  • contains chlorophyll (green colour)
  • only in plant cells
39
Q

Why is chloroplast only in some plant cells?

A

Because it converts energy from sunlight and therefore has to be exposed to light

40
Q

Cilia

A

Cilia are short, hair like appendages extending from the surface of a living cell.

  • short
  • eukaryotic cells
41
Q

Flagella

A

Flagella are long, threadlike appendages on the surface of a living cell.

  • long
  • Eukaryotic and prokaryotic cells
42
Q

Difference between the plasma membrane and the cell membrane

A

Plasma membrane is the layer surrounding the organelles and the cell whereas the cell membrane is the layer surrounding the cell

43
Q

Plasma membrane

A

AKA cell membrane
The partially permeable boundary of the cell separating it from its physical surroundings
Can exclude some substances from entering the cell while permitting entry of others

44
Q

Structure of the plasma membrane

A

2 major components;
Phospholipids - bilayer
Proteins

45
Q

Phospholipids

A

2 fatty acids joined to a phosphate group
Contains hydrophilic head (phosphate)
contains hydrophobic tail (fatty acid )

46
Q

The hydrophilic and Hydrophobic arrangement

A

Hydrophilic heads are exposed to the external/internal

Hydrophobic tails face each other

47
Q

Why is the plasma membrane flexible?

A

due to the fatty acids which are fluids and therefore flexible. this enables them to change shape

48
Q

2 different types of proteins

A

Integral

Peripheral

49
Q

Integral proteins

A 
Are transmembrane (span the width of the membrane)
have protein exposed on both sides
50
Q

Glycoprotein

A

When carbohydrate groups are attached to the exposed part of the protein on the external side

51
Q

Peripheral proteins

A

Anchored to the exterior of the membrane

52
Q

Functions of the plasma membrane

A

Active and selective boundary
Denotes cell identity
Receives external signals
Transports materials

53
Q

Factors that affect substances crossing the membrane

A

Size
Presence of charge (polar)
Solubility in lipids
Direction of concentration gradient

54
Q

Molecular size

A

Some molecules are too big to fit across the membrane, the smaller ones can fit through the gaps ie; macromolecules

55
Q

Presence of a charge (polar)

A

The bilayer is non-polar and therefore charged ions cannot cross the membrane

56
Q

Solubility in lipids

A

Lipophilic molecules can cross easily but hydrophilic molecules cannot cross due to being repelled by water

57
Q

Direction of concentration gradient

A

Movement against the concetration gradient requires energy and is much harder than with the concentration gradient

58
Q

Ways of crossing the boundary

A

Simple diffusion
Facilitated diffusion
Active transport
Endocytosis/exocytosis

59
Q

Simple diffusion

A

Net movement of substances across the membrane from a region of high concentration to low concentration until it reaches an equilibrium

  • passive
  • aims for equal concentration on both sides
  • across a semi-permeable membrane
  • for smaller, uncharged atoms
60
Q

Osmosis

A

Movement of water across a semipermeable membrane

  • From an area of higher water to an area of lower water
  • From an area of low concentration to higher concentration
61
Q

Hypotonic

A

having lower solute concentration than the cell contents

62
Q

Isotonic

A

Having an equal solute concentration to that of the cells

63
Q

Hypertonic

A

Having higher solute concentration than the cell contents

64
Q

Water content in animal cells

A

Too much causes it to burst

Less causes it to shrink

65
Q

Water content in plant

A

Too much causes membrane to swell and cell wall prevent breakage
Too little water causes the plasma membrane to break away from the cell wall

66
Q

Facilitated diffusion

A

It is diffusion that is enabled by special protein transporters in the membrane, allows molecules that can not diffuse across the plasma membrane through channel proteins or carrier proteins
- passive

67
Q

Channel proteins

A

They are transmembrane and have a pore that allows charged particles through

68
Q

Carrier proteins

A

Is a specific size and shape to allow certain particles through, acting like a gate

69
Q

Photosynthesis equation

A

6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O

70
Q

Rates of diffusion (simple)

A

The higher the concentration gradient the faster the substance will move by simple diffusion across a plasma membrane.

71
Q

Rates of diffusion (facilitated)

A

The higher the concentration gradient the faster a substance will move across a membrane to a certain point when all the transporters are fully occupied.

72
Q

Active transport

A

Moving dissolved substances from an area of low concentration to an area of high concentration
- active (requires energy)

73
Q

Endocytosis

A

Is bulk transport of material into a cell
phagocytosis - solid
pinocytosis - fluid
Energy requiring process

74
Q

Exocytosis

A

Bulk transport of material out of the cell
Energy required
Use of golgi body

75
Q

Different microscopes

A

Light (optical) microscope

Electron (transmission) microscope

76
Q

Differences between microscopes

A

Optical has lower levels of resolution and magnification
Optical is coloured, electron is b/w
Optical can be used for living cells

77
Q

What organelles can not be seen with light microscope?

A

Ribosomes
Mitochondria
Peroxisomes

78
Q

Living organisms can only exist where;

A

There is an energy source
Liquid water
Chemical building blocks (C,O,N,H)
Stable environmental conditions

79
Q

Difference between prokaryotic and eukaryotic cells?

A

A prokaryotic cell is a very simple cell which contains no membrane-bound organelles and has a nucleoid which is circular DNA whereas a eukaryote is a very complex cell with many membrane-bound organelles

80
Q

How does the cell maintain its essential functions

A

A constant exchange of material between the cell and its external environment

Biology Unit 1+2 (9 decks)

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