Life Processes: Cell Structures:
- Animal cells have a nucleus, cell membrane,
cytoplasm, mitochondria
- Plant cells have a nucleus, cell membrane,
cell wall, cytoplasm, chloroplasts, mitochondria,
large sap vacuole
- The nucleus stores the genetic data, Chromosomes
- Cell membrane allows substances to pass
through
- Cytoplasm gives a cell it’s shape and allows
substances to pass
- Mitochondria is the powerhouse of the cell,
provides energy
- Chloroplasts in plant cells contains chlorophyll which provide photosynthesis
- Large sap vacuoles in plants help support the
plant cells
- Cell walls in plants provide structural support and protection - Levels of Organization in an organism:
o Organelles Cells Tissues Organs Organ Systems Enzymes:
- Enzymes are biological catalysts and speed up and/or control reactions, which can be affected by temperature and pH levels
- Enzymes are proteins and therefore can be denatured (NOT killed!!!)
- On the protein, there is an active site, where the substrate attaches and is broken up
- The shape of the active site depends on the pH and temperature Cellular Respiration:
- Aerobic Respiration:
o 6O2 + C6H12O6 6CO2 + 6H2O + Energy (Remember: 6, 6, 6 for
balanced equation)
o Oxygen + Glucose Carbon Dioxide + Water + Energy - Anaerobic Respiration:
o C6H12O6 2C3H6O3
o Glucose Lactic Acid Movement of Substances:
- Substances can move into and out of cells by diffusion, osmosis (diffusion specific for water) and active transport and this is affected by concentration, temperature and surface area
- Diffusion is the net movement of particles from an area of high concentration to an area of lower concentration.
o Randomly caused Characteristics of Living Things: - Movement - Respiration - Stimuli - Homeostasi s - Growth - Reproductio n - Excretion - Nutrition
o Is passive and therefore doesn’t require energy
- Osmosis is a special kind of diffusion, where it only happens through a partially permeable membrane
- Active transport is when substances are moved against the concentration gradient (which is high to low) or through a selectively permeable
membrane and it uses energy
Variety of Organisms:
Major Groups: Plants, Animals, Fungi, Protoctists, Bacteria and Viruses - Plants and humans are always multicellular
o Plants carry out photosynthesis
o Animals eat other living things to obtain their energy - Fungi can either be unicellular or multicellular
o They absorb food from other living things - Protoctists are mostly microscopic and single celled - Bacteria are microscopic single-celled organisms.
o They are smaller than Protoctists
- Viruses are non-living parasites that reproduces inside other living cells o They are smaller than Bacteria
- Bacteria, Viruses, Protoctists and Fungi can be pathogens and cause disease Plants:
- Photosynthesis through Carbon Dioxide and Water to make Sugar and Oxygen
o Captured through the sun with their chlorophyll in their chloroplasts - Chloroplasts store carbohydrates such as starch
- Plant cell walls are made out of cellulose Animals:
- Doesn’t contain chlorophyll
- Animal cells don’t have a cell wall
- Most animals have a nervous system for co-ordination - Glycogen, a carbohydrate, is stored in animal cells Fungi:
- Fungi are saprophytes or parasites - Some are multicellular
o E.g. Mushrooms and molds - Some are unicellular
o E.g. yeast
- Fungal cell walls are made of chitin
- Multicellular fungi are made of mycelium, which is a network of structures called hyphae
- Fungi make enzymes and digest their food outside of their cells - Many fungi act as decomposers
- Some Protoctists make their own food via photosynthesis such as algae and others feed on other organisms
Bacteria:
- Tiny, single celled - Common shapes:
o Spheres – singles, pairs, chains or groups o Rods – singles, chains, with or without flagella o Spirals
- Complex cell wall made of polysaccharides and proteins. - Bacteria DO NOT have a nucleus
- They contain small circles of DNA called plasmids
- Some can photosynthesis because they contain chlorophyll - Most bacteria feed on dead or living things
- Some bacteria have slime capsules for protection or flagella (little “tails”) for movement
Prokaryotes:
- Single celled organisms that have no nucleus - Most are bacteria but also include archaea Viruses:
- All are parasites and all natural viruses cause disease - Can only reproduce inside the cells of the host
- Very simple and are found in multiple geometric shapes o Core of genetic material surrounded by protein coat - Viruses either contain RNA or DNA
Breathing and Gas Exchange
- The respiratory system takes air into and out of the body to supply oxygen and get rid of carbon dioxide from the body
- The movement of air from and to the lungs creates a steep concentration gradient for the diffusion of oxygen and carbon dioxide
- The complete respiratory system includes o Ribs
o Intercostal Muscles (Internal and External) o Diaphragm
o Trachea o Bronchi o Bronchioles o Alveoli
o Pleural Membranes of the Thorax
- The alveoli have specific adaptions for efficient gas exchange Structure of the Respiratory System:
- Nasal Passages – Warm, clean and adds moisture to entering air - Epiglottis – Stops food entering the lungs
- Esophagus – Carries food to stomach - Larynx – voice box
- Trachea – tube with “C” like cartilage rings and is lined with cells making mucus and cilia cells
- Left Bronchus – carries air to lungs - Bronchioles – carries air to lungs
- Alveoli – tiny sacs which allow diffusion of oxygen and carbon dioxide - Diaphragm – Sheet of domed muscle which helps with breathing - Ribs – Bones that protect the lungs
- Internal Intercostal muscles – Pulls ribs down and in when you breathe out - External Intercostal muscles – Pulls rubs up and out when you breathe in - Pleural Membranes – Thin, moist membranes that form an airtight seal
around the lungs
- Pleural Fluid – Fills the pleural cavity and acts as lube so lungs don’t stick to chest
Ventilation of the lungs:
- There is more oxygen and less carbon dioxide in the air of the lungs than in the blood
- The movements of the ribs and diaphragm brings changes in the volume and pressure in the chest cavity
Inhalation:
- Air enters lungs
- Volume of chest cavity expands and pressure in lungs is lower than outside - Diaphragm contracts – diaphragm flattens
- External intercostal muscles contract thus pulling ribs up and out and internal intercostal muscles relax
Exhalation:
- Air is pushed out of lungs
- Volume of chest cavity decreases and pressure in lungs is higher than outside - Diaphragm relaxes – diaphragm becomes dome shaped
- Internal intercostal muscles contract thus pulling the ribs down and in and the external intercostal muscles relax
Alveoli:
- Blood is pumped to the lungs
- Blood passes through the network of capillaries around the alveoli - Carbon dioxide diffuses from the blood into the air
- Oxygen diffuses into the blood from the air
- Oxygenated blood is pumped throughout the body - Gas Exchange in the Alveoli:
o There are adaptions that make the alveoli good at its job The alveoli has a large surface area for more diffusion A rich blood supply to easily carry oxygen away and bring
carbon dioxide
Also creates a constant steep concentration gradient between alveoli and blood
