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biology - core concepts > cell structure and organisation > Flashcards

cell structure and organisation Flashcards

(111 cards)

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1
Q

what are the two equations for magnification?

A

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

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2
Q

what is the nucleus composed of?

A

nuclear envelope
nucleoplasm
chromatin
nucleolus

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3
Q

what is the function of the nucleus?

A

to retain the genetic information (DNA) which codes for protein synthesis

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4
Q

what is the nuclear envelope?

A

a double membrane with pores to allow the transport of mRNA and ribosomes out of the nucleus to the cytoplasm

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5
Q

what is the nucleoplasm?

A

cytoplasm-like material within the nucleus which contains chromatin

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6
Q

what is the chromatin?

A

made up of coils of DNA bound to histone protein.
during cell division, the chromatin condensed to form the visible chromosomes

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7
Q

what is the nucleolus?

A

within the nucleus are one or more small spherical bodies, each called nucleolus.
they synthesise ribosomal RNA

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8
Q

what is the function of mitochondria?

A

to release energy in the form of ATP during aerobic respiration

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9
Q

what is the mitochondria composed of?

A

double membrane and intermembrane
cristae
matrix

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10
Q

describe the intermembrane

A

mitochondria have a double membrane with a narrow, fluid-filled intermembrane space

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11
Q

what is the cristae?

A

the inner membrane is folded inwards to form extensions called cristae,
the cristae increase the surface are for ATP synthesis to occur

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12
Q

what is the matrix?

A

contains many chemical compounds including lipids proteins small ribosomes and a small circle of DNA to allow self replication in responds to the energy requirements of the cell.w

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13
Q

what is the function of ribosomes?

A

to assemble proteins in protein synthesis

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14
Q

describe the structure of ribosome

A

the small subunit and large subunit of a ribosome are made of RNA and protein

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15
Q

how does the structure of ribosomes help with protein synthesis?

A

protein synthesis (translation) occurs at ribosomes
mRNA from the nucleus fits into the groove between the two subunits and provides the code for a sequence of amino acids

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16
Q

where are ribosomes found?

A

they are found free in the cytoplasm
associated with rough endoplasmic reticulum

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17
Q

what is the cell membrane also known as?

A
  • plasma membrane
  • phospholipid bilayer
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18
Q

why is it important that the sample must be thin when preparing a microscope slide?

A

to ensure that all structures are 2D, visible and not overlapping

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19
Q

why is it important that the sample should be stained when preparing a microscope slide?

A

to be able to see clear structures visibly

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20
Q

why might staining sometimes be a disadvantages?

A

it can cause misconceptions and organelles are not actually coloured

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21
Q

describe the rough endoplasmic reticulum

A

the rough endoplasmic reticulum is an internal system of flattened membranous sacs, or cisternae, which are continuous within the nuclear membrane

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22
Q

what is the rough endoplasmic reticulum covered in?

A
  • it is covered in ribosomes
  • it gives a dotted appearance and gives it its name
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23
Q

describe the smooth endoplasmic reticulum

A

the smooth endoplasmic reticulum is similar in structure to the rough endoplasmic reticulum but has no ribosomes

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24
Q

what is the role of the smooth endoplasmic reticulum?

A

it is involved in the synthesis and transport of lipids

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25
which type of cells have the smooth endoplasmic reticulum?
cells that store large quantities of carbohydrates, protein or fat e.g liver and secondary cells
26
what is the golgi body made up of?
it is made up of interconnected flattened membranous sacs
27
define organelle
a specialised structure with a specific function inside a cell
28
define magnification
the number of times bigger an image is than the actual size of the object from which it is derived
29
define chromatin
coils of DNA bound to histone protein
30
define eukaryote
organisms made of cells that have membrane-bound organelles, with DNA within the nucleus in the form of chromosomes
31
define prokaryote
single celled organisms lacking membrane-bound organelles, such as nuclei, wit DNA free in the cytoplasm
32
define cristae
folds in the inner mitochondrial membrane
33
define tissue
an aggregation of specialised cells carrying out a specific function
34
define organ
an aggregation of several tissues that carry out a specific function for the whole organism
35
define organ system
two or more different organs working together to provide a common function
36
define organism
all the systems of the body working together, make an organism, which is a discrete individual
37
name 3 specialised plant cells
palisade cell guard cell root hair cell
38
name 5 plant tissues
xylem phloem palisade spongy mesophyll upper epidermis
39
what is the function of the xylem?
transport of water and dissolved minerals
40
what is the function of the phloem?
transport of sucrose and amino acids
41
what is the function of the palisade?
photosynthesis
42
what is the function of the spongy mesophyll?
some photosynthesis provides air space for diffusion of gases in/out of the leaf
43
what is the function of the upper epidermis?
contains cells that are found on the top surface of a leaf ; protected by a waterproof waxy cuticle
44
name 3 plant organs
petal leaves stem roots
45
what are the 4 primary tissue types in the human body?
1. epithelial tissues 2. muscle tissues 3. connective tissue 4. nerve tissue
46
define epithelial tissue
forms a continuous layer, covering or lining the internal and external surfaces of the body
47
how many types of epithelial tissue are there?
4
48
what are the names of the types of the epithelial tissue?
1. squamous epithelium 2. cuboidal epithelium 3. columnar epithelium 4. ciliated columnar epithelium
49
describe squamous epithelium
flattened cells found lining body cavities, such as the mouth and alveoli
50
describe cuboidal epithelium
cube-shaped cells found lining the kidney tubules and ducts of glands
51
describe columnar epithelium
elongated column-shaped cells that are found lining the stomach and intestines
52
describe ciliated columnar epithelium
column-shaped cells that have fine hair-lik projections (cilia) on the surfcde e.g in the trachea, oviduct
53
describe connective tissue
connects and anchors structures and gives strength and support to the body and its organs
54
give an example of a connective tissue
collagen
55
what is the function of collagen?
forms extracellular fibres that give strength to dense connective tissues such as the tendons and ligaments
56
where is collagen found?
tough outer layer of large blood vessels
57
describe muscle tissue
nerve impulses bring about muscle contraction, causing the muscle to shorten as the contraction of the muscle ends, normal muscle length is once again attained
58
what are the 3 examples of muscle tissue?
cardiac muscle skeletal muscle smooth muscle
59
what is the major role of the skeletal system?
support
60
what is the major role of the muscular system?
movement
61
what is the major role of the circulatory system?
transport of gases and nutrients
62
what is the major role of the reproductive system?
reproduction
63
what is the major role of the endocrine system?
homeostatis
64
what is the major role of the excretory system?
removal of waste
65
what is the major role of the digestive system?
to breakdown food and absorb nutrients
66
what is the major role of the nervous system?
coordination and control
67
what is the major role of the respiratory system?
to exchange gases between blood and air
68
what is the major role of the immune system?
protection from pathogens
69
define organism
all the systems of the body working together to make and organism which is a discrete individual
70
define division of labour
the adaptation of different parts of an organism to carry out different functions the more advanced the organism the greater the division of labour
71
define multicellular
organisms consisting of many specialised cells which form tissues and organs, which have various structures and organs
72
define unicellular
single celled organisms which carry out all life functions within one cell
73
define differentiation
the process by which a stem cell becomes specialised into a specific type of cell
74
name 5 specialised cells in the human body
1. red blood cell 2. egg cell (ovum) 3. epithelial cell 4. nerve cell 5. sperm cell
75
what are viruses made up of?
made up of nucleic acid surrounded by a protein coat some viruses have DNA while others contains RNA
76
what is the name of the virus that attack bacteria?
bacteriophages
77
why are viruses described as acellular?
they are not made of cells
78
why can viruses only reproduce inside a host cell?
- they do not have organelles, enzymes, chromosomes or cytoplasm - without ribosomes, they cannot carry out protein synthesis - without enzymes, they cannot replicate nucleic acid
79
how can viruses be transmitted?
- aerosol - insect vectors - exchange of bodily fluids - bites by parasites
80
give 3 examples of viral infections
1. small pox virus 2. polio 3. tobacco mosaic virus
81
how do viruses reproduce inside the host cell?
they hijack the host cell's metabolism they use the host cell's organelles and enzymes
82
what structures do both plants and animals have?
- golgi - nucleus - ribosome - mitochondria - endoplasmic reticulum - lysozyme - cell membrane
83
what is a chloroplast made up of?
- stroma - outer membrane - granum - thylakoid - inner membrane
84
describe stroma
- a colourless, gelatinous matrix - contains small ribosomes, circular DNA (for self replication), lipids and starch grains
85
what are thylakoids?
flattened sacs in the stroma
86
thylakoids are stacked to form ....
grana
87
grana connect to each other by ...
lamellae
88
what is the function of chloroplast?
the site of photosynthesis
89
where is chlorophyll found?
within each thylakoid
90
what does the endosymbiotic theory state?
organelles such as chloroplast and mitochondria were originally free living prokaryotic cells
91
what are the main functions of the golgi body?
- modifying and packaging proteins into secretory vesicles - secreting carbohydrates - producing glycoprotein - transporting and storing lipids - forming lysosomes
92
describe lysosomes
single membrane bound vesicles that contain hydrolytic ezymes
93
how many functions of lysosomes?
2
94
what is the first function of the lysosome?
release hydrolytic enzymes when the cell needcs to break down worn-out organelles
95
what is the second function of the lysosome?
digest material that has been taken to a cell e.g lysosomes fuse with the vesicle made when a white blood cell engulfs bacteria, and their enzymes digest the bacteria
96
how are phospholipid molecules arranged?
as a bilayer, with one sheet of phospholipid molecules opposite another
97
explain why the hydrophobic tails of both layers point towards the inside of the membrane
- the fatty acid tails are non-polar (hydrophobic) and repel water present in the cytoplasm and extracellular fluid - the phosphate heads are polar/ hydrophilic and are attracted to the water
98
describe proteins in the membrane
- globular - can be foujnd on surface - partly embedded (extrinsic) - extending completely across both phosophlipid layers (intrinsic)
99
where are carbohydrates found in the membrane?
only pointing of the outside of the cell
100
why is the model of the cell membrane called the fluid mosaic model specifically?
FLUID : the individual phospholipid molecules and proteins can move freely within a layer relative to one another, this makes the membrane fluid MOSAIC : randomly distributed protein molecules that vary in shape and size forming a mosaic pattern
101
what is the main function of the cell membrane?
to aid transport of certain substances into/out of cell e.g to obtain oxygen and remove carbon dioxide
102
what is the function of phospholipids?
forms a selective bilayer that allows non polar or uncharged molecules through but prevents the passage of polar or charged molecules
103
what is the function of extrinsic proteins?
associated with one layer only may act as receptors for hormones
104
what is the function of intrinsic proteins?
acts as carriers or channels to allow the passage of charged or polar molecules such as glucose
105
what is the function of glycocalyx?
act as cell to cell recognition e.g white blood cells in an immune response also important in cell adhesion and acting as receptors
106
what is the function of cholesterol?
controls membrane fluidity
107
what is the tonoplast?
a single membrane which covers the vacuole
108
describe the cell sap in a vacuole
a solution which stores chemicals such as glucose, amino acids, minerals and vitamins
109
what is the role of the vacuole?
supporting soft plant tissues
110
describe centrioles
found in animal cells found outside the nucleus consists of two rings of microtubules arranged in hollow cylinders positioned at right angles to one another during cell division, they migrate to opposite poles of the cell and form the spindle
111
describe plasmodesmata
narrow pores in the cell wall of plants fine strands of cytoplasm pass through these allows substance to move between connected cells

biology - core concepts (6 decks)

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