Topic 1.1 - 1.5 Flashcards
(86 cards)
1
Q
Homeostasis
A
The maintaining of equilibrium within a cell
2
Q
Reproduction
A
Production of offspring, asexually or sexually
3
Q
Metabolism
A
All the chemical reactions that take place in a cell
4
Q
Growth
A
Cells dividing, organisms undergoing irreversible change in size
5
Q
Response
A
Responding to environment stimuli eg. change in temperature
6
Q
Excretion
A
Expulsion of waste from cell
7
Q
Nutrition
A
Feeding on nutrients needed to carry out cell functions
8
Q
Cytoplasm
A
The site of all chemical reactions in a cell
9
Q
Zygote
A
Formed when sperm fertilises an egg
10
Q
Embryo
A
Formed when the zygote splits to form two cells, then four, then eight, etc.
11
Q
SA: Vol ratio
A
The ratio of SA of the membrane to the volume of cell, which affects efficiency and necessary diffusion of nutrients, toxins, etc.
Larger cell: smaller SA:Vol ratio: lower efficiency and higher distance to travel
12
Q
Emergent properties
A
The whole is more than the sum of its parts; specific parts function within a whole
13
Q
Tissue
A
Group of cells with similar specialised functions
14
Q
Cell differentiation
A
When cells have a specialised function, for which they develop the ideal structure, gene expression, etc. Happens because a different sequence of genes is expressed in different cell types.
15
Q
Gene expression
A
All cells have the same chromosomes and alleles, however, they all express different genes. This is what specialises them.
16
Q
Diffusion
A
The net movement of anything from a region of higher concentration to a region of lower concentration
17
Q
Explain the treatment of Stargardt’s disease with stem cells
A
Stargardt’s is a genetic disease that causes photoreceptive cells in the retina to degenerate, causing blindness. Stem cells are injected into the eye and move into the retina where they attach themselves and develop into retina cells, improving vision.
18
Q
What is a stem cell?
A
A stem cell is a zygote/early embryo that hasn’t yet differentiated and can differentiate along different pathways into any of the cell types found in an animal.
19
Q
Adult stem cells
A
Adult stem cells/tissue-specific cells are found in small numbers in tissue, they replace existing cells in organs as they wear out
20
Q
Pluripotent stem cells
A
Stem cells can be grown into any kind of tissue in the body.
21
Q
Embryonic stem cell
A
Donated from patients at fertility clinics
22
Q
Induced pluripotent stem cells
A
Regular skin, fat, liver,etc stem cells that scientists have changed to be like embryonic stem cells and be able to become any cell in the body
23
Q
Hydrophobic
A
Water-fearing, repulsed by water
24
Q
Hydrophilic
A
Water-loving, attracted to water
25
Amphipathic
Both hydrophilic and hydrophobic
26
Phosphate head
The hydrophilic part of the phospholipid bilayer - attracted to water, on opposite ends of the bilayer, facing the water. They are polar
27
Hydrocarbon
The hydrocarbon tails are the hydrophobic part of the phospholipid bilayer, facing inwards towards each other, away from water. Made of fatty acids.
28
Cell membrane
Controls what enters and leaves the cell, separates the cell from its environment
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Phospholipid bilayer
Membrane made out of two layers lipid molecules
30
Embedded
In the membrane
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Peripheral protein
Protein the outside of the membrane
32
Cholesterol
A steroid lipid that is found in between tails of phospholipids. It reduces membrane fluidity so that it can better control what substances are able to diffuse through. Without cholesterol, the membrane would break up.
33
What organelles do prokaryotes have?
- cell wall
- plasma membrane
- 70S Ribosomes
- Nucleoid
- Plasmids
- Pili or Pilus
Flagellum
34
What is the function of a cell wall?
Encase cell and provide protection, give cell shape
35
What is the function of a plasma membrane?
Controls what enters and leaves the cell, separates cell from its environment
36
What is the function of 70S Ribosomes?
Are the site of protein synthesis
37
What is the function of a nucleoid?
Contains naked DNA and controls cell activities
38
What is the function of plasmids?
Small circles of DNA that carry a few genes
39
What is the function of Pili?
Small protein projections on the cell wall that helps with adhesion/DNA transfer
40
What is the function of the flagellum?
Helps bacteria in movement
41
What is the difference between eukaryotic and prokaryotic cells?
Eukaryotes are more complex in genetic material and organisation. They are compartmentalised (contain membrane-bound organelles) and have a nucleus
42
What are the advantages of compartmentalisation?
- Enzymes and molecules needed for chemical reactions/cellular processes can be at higher concentrations in organelles instead of throughout the cytoplasm
- Waste can be isolated in organelles instead of spread throughout the cell
- Certain conditions can be isolated and maintained within organelles
- Organelles and the materials can move around the cell
- Saves surface area
43
What is the nucleus for?
- Contains DNA
| - Site of DNA replication and transcription
44
What is the function of the cell membrane?
- Surrounds cell and determines what goes in or out
| - Made from two layers of phospholipids and embedded proteins
45
What is the function of 80S ribosomes?
- Site of protein synthesis
| - Found in the Rought ER and free ribosomes
46
What is the function of the rough Endoplasmic reticulum?
Synthesize proteins for secretion from the cell, which will be carried by vesicles to the Golgi apparatus.
47
What is the function of the smooth endoplasmic reticulum?
Synthesises and stores lipids.
48
What is the function of the Golgi Apparatus?
It processes proteins transported from the rough endoplasmic reticulum.
49
What is the function of lysosomes?
They contain enzymes to break down waste&food
50
What is the function of the vacuole?
To store water and digest food
51
What is the function of a mitochondrion?
Produces ATP (energy) for the cell by the process of cellular respiration. Digests fat if used as energy source.
52
What is the function of chloroplasts?
Produce glucose and other organic compounds through photosynthesis.
53
What are the roles of microtubules and centrioles?
- play a key role in the division of chromosomes (microtubules). They are small cylindrical fibre in the cytoplasm.
- centrioles provide an anchoring point for microtubules, cilia and flagella?
54
What are the different functions of proteins on the phospholipid bilayer?
Hormone binding sites, cell adhesion, immobilised enzymes, cell to cel communication, passive transport and active transport
55
What do hormone binding sites do?
Some proteins that cross the membrane can bind to hormones, which allows cells to detect external conditions (e.g. insulin).
56
Describe adhesion proteins
Adhesion proteins allow cells to form tight junctions with each other. This is vital for forming tissues and organs.
57
Describe immobilised enzymes
They can be embedded on either side of the membrane with active sites exposed, ready to speed up chemical reactions
58
What is cell theory?
- all living things are made from cells
- cells are the smallest units of life
- cells only come from existing cells
59
Evaluate embryonic stem cells
ADVANTAGES:
- have unlimited growth potential
- can differentiate into any cell in the body
- less chance of genetic damage due to accumulations of mutations than with adult stem cells
DISADVANTAGES:
- more risk of beoming tumourous
- likely to be genetical different from adult patient receiving the tisssue
- ethical issues- requires killing of embryo
60
Evaluate adult stem cells
ADVANTAGES:
- fully compatible with adult tissues
- does not kill adult
- less risk of developing malignant tumours
DISADVANTAGES:
- limited differentiation
- less growth potential
difficult to obtain, as they are deep in tissues
61
How is the excretion of metabolic wastes from cells related to the concept of the surface area to volume ratio?
Cells with higher SA::Vol ration can act more efficiently as they have shorter diffusion pathways
62
What is the difference between paramecium and other photosynthetic organims in nutrition?
Paramecium obtains nutrients by feeding on other organisms and storing in food vacuole, then gradually digested. Chlamydomonas is photosynthetic; converting sunlight CO2 into compounds needed for energy and growth
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milimeter to micrometer
times 1000
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milimeter to nanometer
times 1000000
65
Contrast the Davson-Danieli model and the Singer-Nicholson model of the membrane
The DD model proposed peripheral layers of protein adjacent to the phospholipid bilayer, on both sides of the membrane. This would explain why the membrane was so efficient at controlling what diffuses in and out of it. The Singer-Nicholson method proposes that proteins occupy a variety of positions and structures (like transmembrane proteins, peripheral proteins). The proteins are likened to a mosaic, and the phospholipids and proteins being free to move labeled it the fluid mosaic model.
66
Describe the falsification of the DD model
Upon freeze-etching the cell membrane, globular proteins were found throughout it, and were interpreted as trans-membrane proteins. This falsifies the idea of peripheral proteins on either side of the membrane. The structure of extracted proteins was varied in size, some being trans-membrance. Finally, researchers tagged antibodies attached to membrane proteins to cells. Some were tagged red and others green. When the cells fused together, the red and green tags mixed, showing that the membrane is fluid.
67
Distinguish between simple and facilitated diffusion
Simple diffusion is the movement of particles across the phospholipid bilayer in liquids and gases without the aid of a protein. Facilitated diffusion requires a protein (channel or carrier) for material to pass through.
68
What is passive transport?
Channel proteins form pores through the membrane. Small, non charged particles are able to diffuse through them without using energy
69
What is active transport?
Other proteins use ATP to pump substances in and out of the cell. For example, the Sodium and Potassium pump.
70
Describe the Sodium Potassium Pump
It is a protein pump that transports sodium ions out of the cell and potassium ions into the cell. This is to maintain higher concentrations of sodium ions outside the cell & higher concentration of potassium ions.
Sodium ions enter the cell. ATP is used to carry out a conformational change to the protein, so the molecule can pass to the opposite side of the membrane. The protein then returns to its original conformation.
71
What is a hypertonic solution?
When a solution has higher osmolarity that a tissue
72
What is osmolarity?
Total concentration of osmotically active solutes
73
What is osmosis?
The net movement of water from regions with low solute concentration to regions with higher solute concentration
74
Describe endocytosis
When vesicles form by pinching off a piece os plasma membrane to form a vesicle on inside of the membrane which contain materials from outside the cell.
75
What is exocytosis?
When vesicles from inside the cell fuse with the membrane so contents leave the cell
76
Osmoregulators
Maintain homeostasis for osmolarity
77
Osmoconformers
Let their osmolarity match that of the environment (eg. jellyfish)
78
How is waste exreted in insects?
Nitrogenous wastes in insects takes the form of uric acid. Uric acid and ions are movied into the Malphigian tubules. by active transport (this is when filtration happens). Water follows by means of osmosis. Moves to gut 0 water and ions are reabsorbed. The uric acid is the excreted with feces.
79
What is found in a healthy person's urine?
- Water
- Nitrogenous wastes (urea)
- Toxins
- Salts
80
Pelvis
Collecting ducts deliver urine to the pelvis to be passed on to the ureter
81
Ureter
Carries urine to the bladder
82
Medulla
Concerned with the reabsorption of water
83
Cortex
Concerned with the ultrafiltration and selective absorption of blood contents
84
Describe binary fission
Binary fission is the asexual mode of reproduction for prokaryotic cells. During binary fission, a cell makes a copy of its genetic information and cytoplasm and splits in half.
85
Draw a diagrammatic cross-section of the fluid mosaic membrane. Label it correctly, using
these terms: phospholipid bilayer, cholesterol, glycoprotein, integral protein, peripheral
protein.
Check
86
Why does a diet high in plants and plant products have relatively low cholesterol levels
compared with a diet involving high amounts of animal products?
Because cholesterol is found in the membranes of animal cells
