TERM 1 CELLS Flashcards
1
Q
Enzymes
A
Enzymes are protein molecules which speed up reactions by lowering activation energy required for the reaction. They are biological catalysts
2
Q
Enzyme properties
A
ENZYMES are composed of PROTEIN MOLECULES that are often highly folded to create a particular chemical
‘shape’. The ACTIVE SITE (surface) is where reactions temporarily occur involving a SUBSTRATE (reactant). A SUBSTRATE-ENZYME COMPLEX is formed during the reaction which are released from the reaction zone leaving the enzyme unchanged.
They require particular conditions for the reaction to work efficiently. This involves PH, TEMPERATURE and SUBSTRATE CONCENTRATION
3
Q
Catalyst
A
Catalysts are chemical substances that can accelerate (speed up) chemical reactions, are unchanged at
the end of the reaction, and can be reused many times.
4
Q
denaturing
A
This occurs because heat increases the kinetic energy of the enzyme and causes the molecules to vibrate so rapidly and violently that it disrupts the normal alpha-helix and beta sheets in a protein. This cause the bonds too disrupt and uncoil randomly.
5
Q
Eukaryotic Cells
A
Membrane bound (mostly) multicellular organisms which contain a clear defined nucleus and organelles
6
Q
Prokaryotic Cells
A
A single celled organism that does not have a clear nucleus or membrane bound organelles
Bacteria
first cells
most common
we are full of them
7
Q
Unicellular Organism
A
an organism that consists of a single cell
8
Q
Multicellular Organism
A
Multicellular organisms are organisms that consist of more than one cell
9
Q
Cell shapes
A
Sphere: most efficient
Flat: (skin, leaf) large flat surface
Newen: Long, thin cell
10
Q
Animal cell
A
Contains: 1 Nucleus 2 Mitochondria 3 Membrane 4 Ribosome 5 Lyosome 6 Endoplasmic Reticulum (smooth) 7 Golgi Body 8 Cytoplasm 9 Vacuole
11
Q
Plant cell
A
Contains: 1 Nucleus 2 Mitochondria 3 Membrane 4 Ribosome 5 Lyosome 6 Endoplasmic Reticulum (smooth) 7 Golgi Body 8 Cytoplasm 9 Vacuole
Cell wall
chloroplasts
large central Vacuole
12
Q
Nucleus
A
- Control Centre
- Determines how the cell functions and basic structure of the cell
- contains dna + protein
13
Q
Mitochondria
A
Membrane-bound cell organelles that generate chemical energy to power the cell. Stored in adenine triphosphate
In charge of Aerobic respiration.
14
Q
Cytoplasm
A
A thick solution that fills cells, and provides a medium for other organelles to remain suspended.
- comprised of water, salts and proteins
15
Q
Lysosome
A
membrane-bound organelle that contains digestive enzymes.
-They break down excess or worn out parts. Sometimes used to destroy invading viruses and bacteria
16
Q
Cell membrane
A
A biological membrane that separates the interior of all cells from the outside environment (the extracellular space) which protects the cell from its environment.
- protects and allows some things to pass
17
Q
Ribosomes
A
macromolecular cells that perform biological protein synthesis. They link amino acids together.
18
Q
Golgi Appraradus
A
Organelle found in most Eukaryotic cells
- Packages proteins into membrane bound vesicles before being sent to their destination
19
Q
Endoplasmic Reticulum
A
A organelle made from two subunits: rough endoplasmic reticulum and smooth endoplasmic reticulum
- It serves for synthesis, folding , modification and transport of protein.
20
Q
Vacuole
A
A membrane-bound organelle which is present in plant, fungal, protist, animal and bacterial cells
-performs function such as storage, ingestion, digestion, excretion and expulsion of excess water.
21
Q
Fungi cell
A
Contains: Nucleus Ribosome Membrane Lyosome Nucleus Endoplasmic Reticulum (smooth) Nucleolus Mitochondria Golgi Body Cytoplasm Vacuole
cell wall
22
Q
Diffusion
A
The movement from high concentration to low concentration. The difference is called the concentration gradient *in liquids and gas
23
Q
Osmosis
A
Diffusion of water only
24
Q
Hypertonic
A
If environment has too much solute (salt)
Implode
25
Hypotonic
Environment is too watery
| explode
26
Isotonic
Environment is the same as the cytoplasm
27
Endocytosis
Taking in a large particle by incorporating it into the membrane
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Exocytosis
Moving a large particle (hormone) out of the cell
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active transport
Uses cellular energy to move particles against the concentration gradient. Lower concentration -> higher concentration.
30
Cell membrane: in detail
Made from:
1) cytoplasm
2) phosphate
3) Lipids - hydrophobic (repels water)
Cell membrane is a phospholipid bilayer
cell markers identify whether external cells are yours E.g. Bacteria
Recepter protein (thermo-receptor, kemo-receptor to monitor what is going on around)
transport protein (can push things in/out of the cell)
*the membrane is described as a 'fluid mosaic'
The membrane allows some substances to pass through (water) but not others.
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What are humans made from?
(prodomadently)
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Phosphorus
These form atoms which are aranged to make molecules - DNA - Protein - Life
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What are cells made from?
Lipids = (fat/oils) - (C,H,O) But they are long molecules with no much oxygen
Carbohydrate = A compound made from only C,H,O
eg. glucose (C6-H12-O6)
Amino Acids = (C,H,O + N) used to build protein
Nucleic Acid = (DNA or RNA) ( C,H,O,N,P) used as a "code" to assemble amino acids into protein (genes)
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Autotroph
An organism that can make its own food
* They use external energy to turn inorganic compounds into food
e. g. plants, algae and some bacteria
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Plants (energy)
Photo-autotrophs
- Use light energy to perform photosynthesis...
Carbon dioxide + water -> glucose + oxygen
-> transformed into other organic molecules
-> broken down to form ATP energy
Sunlight and inorganic molecules are used by auto troughs to photosynthesise. This produces organic molecules which are needed for cellular respiration to produce ATP or can be built into other organic molecules.
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Heterotrough
An organism which can't make its own food
* get nutrients by consuming other organisms
e. g animals, fungi, most bacteria and protists
Carnivores - animal tissue
herbivores - plant tissue
omnivores - both
Whatever their diet is: they break down food in a series of chemical reaction to release organic compounds
other organisms are consumed by heterotroughs. once digested organic molecules are produced which are used for either cellular respiration - ATP... or built into other molecules.
36
Leaf Structure
Leaf Structure
Epidermis = A single layer of cells on the outside of the leaf. alike to skin
Cuticle = Thin waxy layer. wax is secreted by the epidermis. waterproof; protects cells, prevents water loss, doesn't block light
Stomata = Open and close to control gas exchange
*typically found on the underside.
*not a physical thing... its a place
Guard cells 'guard' the stomate and open/close it
Mesophyll (palasade layer) = to perform photosynthesis and make glucose *contains chloroplasts
Mesophyll (spongy) = to perform photosynthesis and make glucose *less chloroplasts. *more rounded. *cells spread out - gas can easily diffuse in and out of cells.
Vascular bundle = the plants transport system (water, sugar etc) - comprised of; cambium layer, xylem, phloem
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Tissue types
Tissues
1) Epithelial tissue = Cover body surfaces, protects organs and forms glands. also helps with excretion and keeping moistness.
2) Connective tissue = Provides support, ensures that different parts of the body are bound together and protects against damage. vary in density and specialty. Includes; fibrous connective tissue loose and connective
3) Nervous tissue = Comprises the brain, spinal cord and peripheral nerves. Contains nervous tissue which specialises in communication between all parts of the body.
4) Muscle Tissue = contains cells called muscle fibres that are highly specialised for contraction. Skeletal, cardiac, smooth.
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Plant Makeup
1) The shoot tissue = part of the plant above ground. supports, exchanges gases, carries out photosynthesis and reproduction. Includes the stem, reproductive organs and leaves.
2) The root system = the part of the plant below the ground. It is responsible for absorbing water and nutrients from the soil for use by the rest of the plant. The roots, including the root hairs, are organs of the root system.
3) Vascular system = is said to be the third system of plants. It is made up of xylem and ground tissue.
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Organisation of taxonomy
```
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
```
40
Organisation of function
```
Atoms/molecules
Cells
Tissues
Organs
Systems
Organism
Ecosystem
```
41
Evaporation / tension / cohesion / model of transpiration
1) Hypotonic solution
2) Osmosis
3) Xylem tissue is dead. Transport is passive. Transpiration goes in one direction only. Water molecules hold very tightly together (cohesion)
4) Evaporation causes a "pull" that creates tension in the water column.
42
Pressure/flow Model of Carbohydrate Transport
Carbohydrate molecules are moved into phloem cell by active transport (against the concentration gradient). Water moves in through the companion cell by osmosis.
- The 'Sieve' plate is the cross section
43
Pressure / Flow model
Cell contents containing carbohydrate forced through sieve plate (like a value) into neighbouring cells. *Both directions.
Ploem cell swells as water moves in creating pressure
Transport is active. Phloem cells are living... Transport is in both directions.
44
Mammalian Digestion System
Complex food stuffs are eaten, or ingested and are broken down by our digestive system into simpler molecules that can be absorbed into the bloodstream.
Types of digestion:
1) Mechanical = Involes the physical breakdown of food particles. Begins in the mouth through the tearing, cutting, chewing and grinding of food by the teeth. The churning motion of the stomach continues the process. This is to decrease the size of the food which equates in a larger surface area. This allows the enzymes to acted more efficiently in the chemical digestion.
2) Chemical = The process of using digestive enzymes to chemically break down the large, complex molecules so that they can pass through a cell membrane and be used by cells. This utilises enzymes to chemically breakdown
45
Open circulatory system
Found in insects
involves haemolymph -> transport fluid = blood + lymph
The organs are bathed in haemolymph and exchange occurs.
*doesn't transport gases just chemicals. ie. nutrients, hormones
46
Closed circulatory system
- Found in fish, birds, reptiles, amphibians and mammals.
- Heart contracts, forcing blood into the blood vessels, which transports blood to the body cells.
- At the body cells, nutrients, wastes, etc diffuse between the cells and blood
2 types:
1) single - heart has 2 chambers
- only in fish
- heat to gills to body to heart
2) double - heart has 4 chambers
- birds, reptiles, amphibians and mammals
- heart to lungs to heart to rest of body
47
Blood
1) plasma = water 90%, gases, wastes, nutrients, salts, other eg hormones
- suspends the other components of blood so they can be transported
2) red blood cells = bi-concave, disk shaped cells without a nucleus. packed with haemoglobin (protein that binds to oxygen). 45% blood
- transport oxygen around the body
3) white blood cells = large nucleus. 5 types
- help fight infection
4) platelets = cell fragment
- stop blood clotting
48
The heart
made of cardiac muscle (and nerve and connective tissue)
2 atriums
2 ventricles
valves prevent back flow of blood (2 atrioventricules, 2 semular)
49
arteries
consist of...
Muscular layer: contracts and relaxes to control blood flow
Elastic layer: helps to maintain blood pressure by stretching and springing back
Endothelium: inner lining
Connective tissue: tough and fibrous outer-lining
50
Veins
Transport blood towards the heart
- have valves
Elastic layer, muscular layer, connective tissue = tin elastic muscular connective tissue layers. veins don't need to recoil and aren't at risk of bursting
(Wide lumin
51
Adaption
Responses to change
1) Physical - structural change in the organism that suits the environments change (shells shape)
2) Behavioural - Change in activity that suits the environmental change (hibernation)
3) Physiological - Change to internal function that suits the environment (Iguanas move into saltwater)
52
Theory of Evolution
Darwin introduced the theory of evolution by natural selection... "On the origin of species"
You need a population with variation. The population needs to be separated and exposed to difficult selection pressure over time. The individuals will evolve into different species.
53
Evidence of Evolution
1) Comparative anatomy = Comparing structure
- mammels, birds, reptiles, amphibians all share a common structure (pentadactyl limb)
2) Comparative Embryology = All sexually reproducing animals go through the same developmental steps
3) The fossil record = Fossils form a pattern: few + simple fossils from the oldest rocks too many+ complex fossils in the recent rocks.
4) Biogeography = All living things share chemical processes: DNA/enzymes/respiration/cell division etc
5) Biochemistry = The distribution of life around the world
54
Techniques for Dating
1) Relative Dating = involves determining the relative order of past events to find the age of an object in comparison to another
- Stratigraphy = A process involving the comparison of the position of rock strata that contains fossils to determine the comparative time scale of the occurrence.
- Index fossils = fossils that existed during limited periods of time that can be used as guides to determine the relative age of rocks in which they are preserved
2) Absolute dating = Provides a precise estimate of fossils age. Provides a fossils specific numerical age. Quantitative method of dating
- Radiometric Dating = The process of determining the age of fossils from the decay of radioisotopes (unstable atoms) known using half lives
55
Evolution Terms
1) Convergent evolution = different types of animals (mammals, fish, reptiles) take on the same adaption when exported too similar selection pressure
2) Divergent evolution = One types assumes many different forms to occupy niches in the environment
3) Graduation = Change takes place gradually over time *Darwin
4) Punctuated equilibrium = There is little change during a time of stasis (no change) and rapid change during a time of upheaval *is reflected in fossil record
56
Requirements for life
OXYGEN
- On land, evenly distributed, approximately 21% of air
- concentration goes down with altitude
- oxygen is present as a dissolved gas in water
- concentration depends on temperature, depth, amount of organic matter
WATER
- on land availability is variable
- groundwater must be hypotonic for plants
- in the ocean it is unuseable
- saltwater fish drink seawater and produce small volumes of concentrated urine (hypertonic)
- Freshwater fish never drink and produce large volumes of dilute urine.
57
Time on Earth
Half life = the time taken for 1/2 of a sample of an unstable isotope to decay
The age of the earth has been calculated using the decay sequence of Uranium
4.5 billion years old
It started only with prokaryotic cells before "Endosymbiosis" which led to Eukaryotic cells
- Complex cells -> Colonial organisms -> Multicellular -> Cambrium explosion
58
Index Fossils
- Exist in a short vertical range in the fossil record
- Are widespread around the earth
Used a =s a reference point for dating other fossils/rock layers eg emmonite fossils
59
DNA
DNA is a macro molecule made up of repeating nucleotides
Adenine - Thymine
Guanine - Cytosine
They are chemically bonded in a sugar/phosphate chain
*random order
The molecule's can be separated by heating and the halves will re-join when cooled but not as well
DNA codes for protein. protein is made up of amino acids. Every 3 bases code for 1 amino acid. There are 20 amino acids
60
Relationships between organisms
```
Mutualism = both benefit
Commensalism = 1 benefits and the other is unaffected
Parasitism = 1 benefits at the others expense
```
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Sampling
All sampling is only an estimate. The more samples the more accurate
Quadrats = randomly located. used as a sample of a larger similar area.
Transacts = lines run through an area with samples along the length. can be done on vehicles or even aircraft. must be randomly chosen.
62
Animal Sampling
- Sessile (non-moving) animals are sampled with quadrats like plants
- Motile (moving) animals need different methods
1) areal survey
2) citizen scientists (bird count)
3) Capture/tag/re-capture
Population = Capture x re-capture / Tagged when re-captured
for accurate samples - 1%
area/0.25 = required samples
63
Evolution of the horse
The evolution of the horse is one of the best documented in all palaeontology
There is evidence of a horse ancestor about 55 million years ago which appeared dog like with 4 functional hooves on each foot
it experienced an increase in size, reduction in the number of hooves, loss of the footpads, lengthening of the legs, fusion of the independent bones of the lower legs, elongation of the muzzle, increase in the size and complexity of the brain, and development of crested, high-crowned teeth suited to grazing.
64
evolution of the platypus
Mammal like reptiles diverged from the lineage they shared with birds and reptiles about 280 million years ago.
Streamline body. broad, flat tail are covered with dense waterproof fur, which provides excellent thermal insulation. The Platypus propels itself through the water by using its front, short, webbed limbs, and the partially-webbed hind feet act as rudders.
Behind its distinctive bill are the grooves that house the ear openings and the eyes which close when the animal dives. The Platypus uses its tail for storage of fat reserves and the strong claws on its feet for burrowing and moving on land. In addition, males possess a horny spur on their ankles, which is connected to a venom gland in the upper leg, making the Platypus one of the few venomous mammals.
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equation for photosynthesis
light energy
carbon dioxide + water --> glucose + oxygen + water
chlorophyll
66
Endosymbiotic theory
evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms.
proof:
1) Mitochondria and chloroplasts have their own DNA that is arranged in a similar way to prokaryote DNA
2) They are also similar size and divide in similar ways
3) Still happening today! Termites have prokaryotes (bacteria) that live in their gut and help them digest wood.
67
Australian Megafauna
4 Theories for Megafauna extinction
1) Overkill — hunting by humans in an unsustainable fashion.
2) Change in Climate — changing temperatures leading to a loss of biodiversity due to adaption being too slow.
3) Disease — An introduction of humans to Australia may have brought diseases that humans have adapted too but animalia were unable too.
4) Asteroid or Comet — it is possible that space debris led to the extinction of the megafauna however due to the continuation of human life as proved by the Cuddie Springs site it is likely a space object did not lead to extinction of a singular species but not others.
68
Fossil sites
1) Riversleigh, Qld and Naracoorte, SA show the evolution of mammals in Australia over the past 20 million years. It is part of the Naracoorte Caves National Park. Its fossils show the way marsupials adapted to the great climate changes that have affected the world over the last 170,000 years.
2) Cuddie springs is an open site where the fossil deposits have been preserved in the claypan floor of an ancient ephemeral lake. Due to the claypan filling with water after rainstorms and taking months to dry the fossils have survived over a long period of time. The site contains fossils of australian megafauna and is evidence for human coexistence with the fauna.
69
Extinction of the Tasmanian tiger
Tasmanian tigers once lived on the Australian mainland and Papua New Guinea. Tasmanian tigers were hunted and killed by humans and dingoes.
White settlers brought large quantities of livestock with them and assumed that Tasmanian tigers would be livestock killers.
It’s likely the dogs also contributed to the Tasmanian tigers’ decline through direct competition and by introducing new diseases.
70
Microscopes
1) Compound light Microscope
- Consists of lenses which magnifies the image placed under a light
- Inexpensive
2) The Electron Microscope
- Allows you to see images 1 nanometer in size
- used in biomedical research to investigate the detailed structure of tissues, cells, organelles and macromolecular complexes.
71
Cell Theory
all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
72
Endocytosis
a cellular process in which substances are brought into the cell.
73
Exocytosis
Exocytosis is a form of active transport and bulk transport in which a cell transports molecules out of the cell by secreting them through an energy-dependent process.
74
Mitosis
Mitosis is a process where a single cell divides into two identical daughter cells (cell division).
75
Meosis
Meiosis is a special type of cell division in sexually-reproducing organisms used to produce the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately result in four cells with only one copy of each chromosome.
76
Protein
Protein is made of carbon, hydrogen, oxygen, nitrogen and one or more chains of amino acids. The three types of proteins are fibrous, globular, and membrane.
Fibrous = Fibrous proteins form muscle fiber, tendons, connective tissue and bone.
Globular protein = Globular proteins are more water soluble than the other classes of proteins and they have several functions including transporting, catalyzing, and regulating.
Membrane = Membrane proteins play several roles including relaying signals within cells, allowing cells to interact, and transporting molecules.
77
Muscle types
Skeletal: Long and have striations. Attached to bone and their contraction causes movement within the organism. Voluntary
Cardiac: Presents in the heart. Have striations. They have connection junctions that are necessary for the coordinated beating of the heart. Involuntary
Smooth Muscles: Do not have striations and their contractions push substances through specialised organs such as, urethra, blood vessels. Involuntary
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Meristematic tissue
Meristematic tissue
- found at the tips of roots and shoots.
- Meristematic are where cells divide to produce specialised cells can also take place here.
- cube shaped and small
79
Dermal Tissue
Dermal Tissue
- Protect the plant tissue and can be found on the outer layer of the stems, roots and leaves. Protects the plant from damage and control interactions with the plants surroundings.
- secretes a waxy layer called the cuticle, which is vital to reduce water loss from the plant.
- Can produce fine hairs on the surfaces of leaves and stem. Hairs trap a layer or air next to the leaf preventing flow of hair and decreasing evaporation of water.
80
Vascular Tissue
Vascular Tissue
- Responsible for transport of substances around the plant and is found in the roots, stem and leaves.
Two Types:
-> xylem = transports water and mineral salts from roots to leaves. dead. Transport is passive. bottom to top
-> phloem = transports the products of photosynthesis around the plant. live. transport is active. carbohydrate solution. any direction
81
Ground Tissue
Ground Tissue
- All of the internal cells other than the vascular tissue
- Consists of a variety of different cell types that are specialised for food storage, support and photosynthesis.
