2. Core Concepts Cell structure and Organisation Flashcards

(216 cards)

1
Q
  1. how many mm in a m
  2. how many Um in a mm
  3. how many nm in an Um
A

1.1000
2.1000
3.1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

labelled light microscope

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

define magnification

A

how many times bigger the image of a specimen observed is in compared to the actual (real-life) size of the specimen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define resolution

A

Resolution is the ability to distinguish between two separate points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

max resolution of light and electron microscope

A

light 0.2 micrometers

electron 0.002 micrometers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

max magnification of light and electron microscope

A

light x1,500

electron x500,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

function of cellulose cell wall

A

allows high internal pressure, WO bursting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

surface cell membrane image

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

plasmodesmata

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

can animal cells have vacuoles

A

yes, temporary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

the centrosome

A

-two centrioles
-involved in nuclear division of animal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Animal and plant cells similarities and differences

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

division of labour

A

describes specialised functions of cell organelles
-come together to ensure cell is capable of surviving + perform roll in body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

define tissue

A

A tissue is an aggregation (group) of similar cells carrying out the same function.

For example, the layer of cells that line the alveoli in the lungs is a type of epithelial tissue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

define organ

A

Organs are aggregations of several tissues which carry out a function for the whole organism.

For example, the eye contains many tissues all of which are needed for the organ to function correctly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

define organ system

A

Organ Systems are groups of organs that work together to carry out a function.

For example, the digestive system has several parts, such as the oesophagus and stomach, and is linked to accessory organs such as the pancreas and gall bladder.

Circulatory = heart blood blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Epithelial tissues

A

Epithelial tissues are made from cells (at least in the bottom layer) which sit on an additional layer of membrane, the basement membrane.

Epithelial tissues are found covering surfaces and are often the sites of absorption of substances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Columnar epithelium

A

These cells are taller than they are wide and are found in many organs of the body, e.g. the small intestine, where the cells are covered in microvilli to increase the surface area for absorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cuboidal epithelium

A

These cells have approximately the same height and width. They can be found lining the proximal convoluted tubules in the kidney. They reabsorb useful substances that are filtered out of the blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Squamous epithelium

A

Squamous epithelial cells are very thin. These cells line the alveoli in the lungs. Being very thin reduces the diffusion distance for the exchange of gases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Stratified epithelium

A

These tissues are made from layers of cells. The bottom layer is in contact with the basement membrane and divides to make the upper layers of the tissue. The top layers are usually dead and they can be worn away without damage being caused to the layers underneath. Examples of this type of tissue are found in skin and the oesophagus (shown below).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Ciliated epithelium

A

Ciliated epithelial cells have a brush border of cilia; these contain protein microtubules that can move.

This type of epithelium is found in the trachea where mucus needs to be moved out of the lungs and in the fallopian tubes where the cilia set up a current to move an embryo into the uterus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is epithelial tissue made of?

A

Cells (at least in the bottom layer) that sit on a basement membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the general functions of epithelial tissue?

A

Covering surfaces and serving as sites of absorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe the structure and function of columnar epithelium.
Tall cells, taller than wide. Found in organs like the small intestine. Covered in microvilli to increase surface area for absorption.
26
Where is columnar epithelium found?
Small intestine and other absorptive organs.
27
What is the structure of cuboidal epithelial cells?
Cube-shaped, roughly the same height and width.
28
Where are cuboidal epithelial cells found and what is their function?
In the proximal convoluted tubules of the kidney; they reabsorb useful substances filtered from the blood.
29
What is the structure of squamous epithelial cells?
Very thin and flat.
30
Where are squamous epithelial cells found and what is their function?
In the alveoli of the lungs; they reduce diffusion distance for gas exchange.
31
What is stratified epithelium?
Epithelial tissue made from multiple layers of cells. The bottom layer touches the basement membrane and divides to make upper layers.
32
What is special about the top layer of stratified epithelium?
The top cells are usually dead and can be worn away without damage to deeper layers.
33
Where is stratified epithelium found?
In the skin and oesophagus.
34
What is the structure and function of ciliated epithelium?
Cells have a brush border of cilia containing protein microtubules that move substances.
35
Where is ciliated epithelium found and what does it do?
Found in the trachea (to move mucus out of the lungs) and the fallopian tubes (to move an embryo into the uterus).
36
Connective tissue:
A tissue that supports or binds other tissues or organs. Contains cells (e.g. fibroblasts, macrophages) and a matrix (non-living material, often with protein fibres like collagen or elastin).
37
Tendons, ligaments, cartilage and areolar tissue
Tendons – connect muscle to bone (rich in collagen for strength). Ligaments – connect bone to bone (contain elastin for flexibility). Cartilage – supportive, flexible, cushions joints. Areolar tissue – loose connective tissue found under skin and around organs.
38
Fibrous Connective Tissue
39
Cartilage
40
Bone Tissue
41
Areolar (Loose Connective) Tissue
42
What is the main function of connective tissue?
To support, connect, or separate different tissues and organs in the body.
43
What type of connective tissue connects muscle to bone?
Tendons
44
What protein makes tendons strong and inelastic?
Collagen
45
What type of connective tissue connects bone to bone?
Ligaments
46
Why are ligaments more flexible than tendons?
Because they contain more elastin fibres.
47
Which connective tissue holds organs in place and is found under the skin?
Areolar (loose) connective tissue
48
Loose connective tissue
Loose connective tissue is found between layers of tissues, e.g. under the skin.
49
Fibrous connective tissue
Fibrous connective tissue is found in tendons and joins muscle to bone.
50
Bone tissue
Bone tissue makes up the skeleton. It provides support and enables movement.
51
Adipose tissue
Adipose tissue stores fat as a source of energy, protection, thermal insulation, and buoyancy.
52
Cartilage
Cartilage is found at the ends of bones and reduces friction during movement. Some cartilage is flexible, e.g. at the ends of the ribs.
53
Blood
Blood is a liquid tissue that transports nutrients, wastes, hormones and heat around the body.
54
Connective tissue
55
muscle tissue
Muscle tissues are responsible for moving parts of the body through contraction.
56
wavelength of an electron microscope
-shorter wavelength than light
57
limitations of electron microscope
-electrons high speed, low energy -specimin needs to be **thin** for electrons to penetrate, otherwise will be -must be **stained with heavy metal ions** eg lead, allows them to absorb electrons -must be under a **vacuum**, air would deflect the electrons and disrupt beam
58
Cross Section of a leaf
59
Electron microscope
60
cytosol
liquid component of the cytoplasm, surrounded by cell membrane around organelles and subcellular structures function: -**transport of molecules across the cell** -provide structural support to organelles -**signal transduction to the target components** -platform for cellular metabolic processes and reactions -maintains gradient across cell membrane
61
signal transduction
process by which a cell signal is transmitted to produce a cellular response
62
cytoplasm
63
definiton of cytosol and cytoplasm
64
composition of cytosol and cytoplasm
65
diversity of cytosol and cytoplasm
66
components of cytosol and cytoplasm
67
metabolism of cytosol and cytoplasm
68
activities of cytosol and cytoplasm
69
functions of cytosol and cytoplasmS
70
ribosomes
71
golgi apparatus
72
rough endoplasmic recticulum
73
vesicle
**small, spherical organelle consists of fluid enclosed by a lipid bilayer ** used to store and transport substances around the cell, digest materials
74
chloroplast membrane
double membrane
75
stroma
aquous matrix contains starch grains
76
grana
thylacoids arranged in flattened circular piles contain photosynthetic pigments
77
lamella
connect and separates thylakoid stacks (grana)
78
chloroplast
79
labelled chloroplast
80
lysomes
small spherical vesicles bound by a single membrane produced in golgi apparatus or ER break down imported food vacuoles -contain enzymes - lysozymes (digestive enzymes) -digest invading cells or worn out cell structures via endocytosis -digested material is used or excreted
81
mitochondrion
-cristae, enables compartmentalisation, allws mitochondria to separate different enzymes for different parts of the respiratory cycle -endosymbiosis, prokaryotic clees englufed by eukaryotic cells
82
-endosymbiosis
prokaryotic clees englufed by eukaryotic cells
83
labelled mitochondrion what does the matrix contain?
matrix - contains enzymes for cell respiration
84
exam Q - draw and label a mitochondria
85
what is the matrix
aqueous solution of metabolites and enzymes, within inner membrane of mitochondrion
86
smooth endoplasmic recticulum
eg lipids, steroids, hormones, also site of storage of calcium ions eg for muscle contraction vesicles with steroid hormones and enzymes to deactivate toxins eg alcohol
87
plasma membrane
88
cellulose cell wall
89
nucleus
90
permanent vacuole
91
nucleolus
92
chromatin | nucleus
genetic material containing (DNA, RNA) functions -prevent DNA damage -tightly packing DNA into cell -control DNA replication and gene expression -support DNA molecule, allow meiosis and mitosis
93
plasmadesmata
adjacent plant cells are linked by channels (pits) cytoplasmic strands join adjacent plant cells
94
temporary vacuoles
may be found in animal cells function (store and trasnport substances) -osmoregulation -storage -excretion -digestion
95
centrioles | animal cells only
96
cell fractionation
organelles extracted form cells and separated analysed: reactions within and enzymes biochemical roles studied
97
conditions of cell fractionation
1. low temperature, prevents autolysis (self-digestion) 2. isotonic solutions, same concentration used, prevents movement of water in or out
98
microtubules
straight, unbranched hollow cylinders in cytoplasm of eukaryotic cells made of globular protein - tubulin involved in movement of organelles in cytoplasm eg spindle fibres
99
cilia
both have 9 pairs of microtubules contain enzymes which release energy from adenine triphosphate cilia - surface of membranes
100
flagella
-help the cell move -microtubules inside
101
pit
in xylem allow water to move sideways between the vessels
102
# - amyloplast (starch grain)
organelles responsible for the storage granules
103
carotene chromoplast
pigment absorbing blue, green light necessary for photosynthesis
104
105
microfilaments
106
peroxisome
107
capsule | prokaryote
108
necleoid | prokaryote
109
pili | prokaryotic
110
cytoplasmic membrane | prokaryotic
111
mesosome | prokaryotic
112
nucleoid and plamids | prokaryotic only
113
Peptidoglycan cell wall
114
What are NAM and NAG in bacterial cell walls?
NAM: N-acetylmuramic acid NAG: N-acetylglucosamine These alternate to form long carbohydrate chains in peptidoglycan. Each NAM has a short peptide chain that allows cross-linking between chains.
115
What is the structure of peptidoglycan?
Made of NAM-NAG chains cross-linked by short peptides. β bonds join sugar units; peptide bonds cross-link chains. Forms a rigid mesh that strengthens the bacterial cell wall.
116
Why is peptidoglycan stronger than cellulose?
Peptide cross-links are covalent, giving greater strength than hydrogen bonds in cellulose. Microfibrils formed from β-bonded NAM-NAG chains further increase structural integrity.
117
What are the functions of the peptidoglycan cell wall in bacteria?
Determines cell shape Protection from toxic substances Prevents osmotic lysis by resisting internal turgor pressure
118
What are the main functions of the bacterial cell wall (peptidoglycan)?
Maintains the shape of the bacterial cell Protects from toxic substances Prevents lysis due to osmotic pressure (protection from osmotic effects)
119
Plasma Membrane
Structure: Phospholipid bilayer with embedded proteins; carbohydrates on extracellular surface. Function: Selectively permeable barrier; cell recognition in eukaryotes.
120
Cytoplasm
121
122
eye piece units
twirl eye piece
123
eye piece graticule
on eye lense
124
calibrating microscope
125
126
epu to smu
5smu=2epu 1smu=0.1mm
127
prokaryote vs eukaryote
p - no membrane bound organelles, circula DNA, small ribosomes, smaller 0.1-0.5Um e- contain membrane bound organelles, linear chromosomes in nucleus, large ribosomes, 10-100Um, most multicellular
128
labelled light microscope
129
130
131
132
133
134
viral envelope
additional layer outside the capsid This is often a phospholipid bilayer which has come from the cell membrane of the host cell. Additional viral proteins / glycoproteins may be present embedded in this layer and are essential to the virus: proteins can be enzymes used to penetrate the cell membrane of a host cell glycoproteins can act as receptor molecules that can bind to and trigger receptor molecules in the host cell membrane. This then causes the virus to be taken into the cell.
135
Why are viruses not considered living organisms?
Viruses lack key features of life: no cell membrane, no cytoplasm or organelles, cannot carry out respiration or produce ATP, do not grow, and cannot reproduce without a host.
136
How do viruses reproduce?
They invade a host cell and use its enzymes, ribosomes, and energy to replicate their nucleic acid and synthesise new viral proteins, assembling new virus particles.
137
What are the basic structural components of a virus?
Nucleic acid (DNA or RNA) Capsid (protein coat made of capsomeres) Viral envelope (in some viruses) derived from host cell membrane Viral enzymes (sometimes present) for replication
138
What is the capsid and what is its function?
The capsid is a protein coat made of subunits called capsomeres. It protects the viral genetic material and helps in attaching to host cells.
139
What type of genetic material do viruses contain and what does it code for?
Viruses contain either DNA or RNA, never both. It codes for essential proteins like capsid proteins, envelope proteins (if present), and replication enzymes.
140
What is the viral envelope and what is its origin?
It's an outer phospholipid bilayer in some viruses, derived from the host cell membrane during viral budding. It may contain embedded proteins and glycoproteins.
141
What are the roles of proteins and glycoproteins in the viral envelope?
Proteins may be enzymes that help the virus penetrate the host membrane. Glycoproteins act as receptors, binding to host cell receptors and triggering endocytosis or membrane fusion for viral entry.
142
diagram shows the structure of (a) a simple virus and (b) a virus surrounded by an additional viral envelope.
143
What is exocytosis?
Exocytosis is the process by which cells secrete substances by vesicles fusing with the plasma membrane, releasing their contents outside the cell and adding new membrane to the plasma membrane.
144
What are the key features of exocytosis?
Involves the fusion of vesicles with the plasma membrane. Releases substances (e.g., hormones, enzymes) outside the cell. Increases the surface area of the plasma membrane.
145
What role do vesicles play in exocytosis?
Vesicles contain substances to be secreted. They move towards the plasma membrane, fuse with it, and release their contents outside the cell.
146
Why is exocytosis important for cells?
It allows cells to release important substances like hormones, neurotransmitters, and digestive enzymes. It also helps add membrane material to the plasma membrane.
147
Can you provide an example of exocytosis in the body?
Exocytosis is involved in the release of neurotransmitters at synapses between neurons, and the secretion of insulin by pancreatic cells.
148
What is the mechanism of exocytosis?
A vesicle containing substances to be secreted moves toward the plasma membrane. The vesicle fuses with the membrane. The contents are released outside the cell. The vesicle membrane becomes part of the plasma membrane, increasing its surface area.
149
How does exocytosis differ from endocytosis?
Exocytosis is the process of expelling substances from the cell. Endocytosis involves the intake of substances into the cell by engulfing them in vesicles.
150
What is endocytosis?
Endocytosis is the process by which cells take in substances from their external environment by engulfing them in vesicles formed from the plasma membrane.
151
What are the types of endocytosis?
The main types of endocytosis are: Phagocytosis (cell engulfs large particles). Pinocytosis (cell ingests fluids and dissolved solutes). Receptor-mediated endocytosis (cell takes in specific molecules by binding them to receptors on the membrane).
152
The diagram summarises how the nucleus, endoplasmic reticulum, Golgi body and plasma membrane work together:
153
What is transcription and where does it occur?
Transcription is the process of copying a gene's DNA sequence into messenger RNA (mRNA). It occurs in the nucleus.
154
What is the role of the nucleolus in protein synthesis?
The nucleolus is responsible for producing ribosomal RNA (rRNA) and assembling ribosome subunits, which are essential for translation.
155
How does mRNA exit the nucleus?
mRNA exits the nucleus through nuclear pores, entering the cytoplasm to be translated by ribosomes.
156
What is translation and where does it occur?
Translation is the process where ribosomes read the mRNA sequence to assemble amino acids into a polypeptide chain. It occurs in the cytoplasm.
157
What is the role of the rough endoplasmic reticulum (RER) in protein synthesis?
The RER is studded with ribosomes and facilitates the folding and modification of newly synthesized polypeptides, preparing them for transport.
158
How are proteins transported from the RER to the Golgi apparatus?
Proteins are enclosed in vesicles that bud off from the RER and move to the Golgi apparatus for further processing.
159
What modifications occur in the Golgi apparatus?
In the Golgi apparatus, proteins undergo further folding, addition of carbohydrate chains (glycosylation), and are sorted and packaged into vesicles for their final destination.
160
How are proteins secreted from the cell?
Proteins are packaged into secretory vesicles that fuse with the plasma membrane, releasing their contents outside the cell via exocytosis.
161
What is the role of tRNA in translation?
Transfer RNA (tRNA) brings specific amino acids to the ribosome, matching its anticodon with codons on the mRNA to ensure the correct amino acid sequence.
162
What is the significance of the start and stop codons in mRNA?
The start codon (AUG) signals the beginning of translation, while stop codons (UAA, UAG, UGA) signal its termination, ensuring proteins are synthesized correctly.
163
Protein synthesis Diagram
164
165
low power plan
When drawing a low power plan, it is important to use an eyepiece graticule to measure key dimensions (e.g. width and height of tissue layers) so that your drawing is in proportion to the actual dimensions of the specimen.
166
conversion between units
167
IAM
168
169
What is phagocytosis?
Phagocytosis is a type of endocytosis where the cell engulfs large solid particles, such as food or pathogens, forming a phagocytic vesicle.
170
What is receptor-mediated endocytosis?
Receptor-mediated endocytosis is a form of endocytosis where the cell selectively takes in specific molecules by binding them to receptors on the plasma membrane, followed by vesicle formation.
171
How does phagocytosis work?
The cell extends its plasma membrane around the particle (e.g., bacteria). The membrane engulfs the particle, forming a phagocytic vesicle. The vesicle is internalized, and the particle can be degraded or processed within the cell.
172
Why is endocytosis important for cells?
Endocytosis allows cells to take in nutrients, remove waste products, and defend against pathogens. It also facilitates the internalization of signaling molecules and the regulation of receptor levels.
173
How does endocytosis affect the plasma membrane surface area?
Endocytosis decreases the surface area of the plasma membrane because the membrane is used to form vesicles that are internalized into the cell.
174
175
part ii
176
virus vs human cell
177
how is a virus RNA replicated and used to make a protein
178
179
180
181
182
enzyme experiments why use ice
to reduce KE of enzymes
183
(iv) Both mitochondria and chloroplasts are believed to have evolved from prokaryotes. What evidence does the graph provide that could support this hypothesis? Explain your answer. [2]
184
185
Name the organelle shown in Image 3.2 and suggest its function in enzyme secretion. [3]
186
how does mitochondria self replicate
187
188
189
190
ATP synthase is the enzyme that uses the energy from the flow
of protons (down their concentration gradient) to synthesise ATP from ADP + Pi (inorganic phosphate).
191
2 places a channel protein is found in a eukaryote cell
192
193
how are mitochondria adapted to carry out respiration
194
how are chlorophyll adapted for photosynthesis
195
Endosymbiont Theory
Endosymbiont theory proposes that mitochondria and chloroplasts originated as free-living prokaryotic (bacterial) cells that were engulfed by an ancestral eukaryotic cell and became symbiotic over time.
196
Evidence that mitochondria and chloroplasts evolved from bacteria:
197
198
199
200
201
when does crossing over occur
meiosis 1 prophase
202
when does random assortment occur
metaphase 1
203
204
why is there a small chance crossing over will occur
205
mitotic index of root close and far away
206
207
208
define hydrolysis
209
210
how pH and temp affect enzymes
211
212
Effect of changes on levels of protein structure
213
eg insulin effect of structure change on functionality
214
A symbiotic relationship is the interaction between two different species living in close physical association to the advantage of both. In 1967, Lynn Margulis proposed the theory of endosymbiosis and suggested that mitochondria and chloroplasts evolved from free-living prokaryotes that were taken into other prokaryotic cells by endocytosis to form the first eukaryotic cells. Suggest the advantages of this symbiotic relationship to the mitochondria, the chloroplasts and the newly formed eukaryotic cell.
Describe and explain how the double membrane observed in both organelles was formed, and how this supports the theory of endosymbiosis.
215
A symbiotic relationship is the interaction between two different species living in close physical association to the advantage of both. In 1967, Lynn Margulis proposed the theory of endosymbiosis and suggested that mitochondria and chloroplasts evolved from free-living prokaryotes that were taken into other prokaryotic cells by endocytosis to form the first eukaryotic cells. Describe and explain how the double membrane observed in both organelles was formed, and how this supports the theory of endosymbiosis.
216
Compare the structures of mitochondria and chloroplasts to prokaryotes.
Circular DNA for self-replication 70S ribosomes Double membrane Similar size (1–10 μm) Chloroplasts contain chlorophyll (like photosynthetic bacteria) Mitochondria have cristae (like mesosomes in bacteria)