Biology Exam #2 🍃
Genes
Ecology
Plants #
Photosynthesis
Microorganisms
Bacteria (Monera)
Natural Selection
Respiration
Mostly unicellular
Others are Multicellular - Chains of cells
Kingdoms
Monera
Protista
Fungi
Simplest and smallest life forms
No Nucleas
Single Cell
Group of mostly multi-cellular organisms
Larger unicellular organisms
With Nucleas
Many Different types of Prostita
Organisms which are too small to be seen with the naked eye. Therefore we use microscopes
Each Micro-organism carries out all the life processes (MRS GREN)
Many act as decomposers, recycling carbon and nitrogen as they break down dead organisms
Reproduction
Usually they are fast, actively growing but can also be dormant spores
Most Unicellular organisms reproduce by Binary Fission
Spores are small cells that float in the air until it finds suitable conditions to germinate (begin to grow) and begin-multiplying.
The cell grows to a certain size and makes a copy of its genes (doubles nucleus or just the DNA)
Then divides into two smaller cells, each with a copy of the genes
This process can be extremely rapid. Bacteria in our gut can divide every 20 minutes (exponential growth)
Meaning that there would be 64 million bacteria after 12 hours #
They are unhelpful when they make food grow mould or go off
By using digestive organisms
- There is competition within the population (eg. for food)
- The individuals with characteristics suited for the environment are more likely to survive and reproduce - Survival of the Fittest
- These survivors will pass on these alleles (mutations of a gene) for improved adaptations to their offspring who also show this beneficial variation.
- The frequency of this allele will increase over the next few generations
- Genetic Variation (caused by mutations) is present in the ancestral population
Clones
Identical twins are another example of natural clones in animals
It is possible to artificially clone organisms, which has become a controversial issue
Organisms which reproduce asexually form natural clones (eg. Micro-organisms)
To Clone a Sheep (or mammals generally):
Take cell from Dolly's genetic mother and separate the nucleus from the rest of the cell. This cell is called the Somatic Cell.
Take an unfertilised egg from another mammal (in this case another female sheep) and remove the nucleus. This is now called the Enucleated Cell
Fuse the the nucleus from the Somatic Cell and the Enucleated Cell
Wait as the new DNA and egg cell needs time to adjust to each other
To fertilise the cell, add some chemicals that simulates the sperm fertilising the egg
Wait until cell has divided into 16 cells in the petri dish
Now transplant the fertilised cell into a uterus of a female sheep (the surrogate donor)
The sheep should have a normal pregnancy and birth
The sheep should be a clone of the Dolly's generic mother (the nucleus)
Leaves
Cell
Pili
Nucloid region
Flagella
Plasmid
Cell Membrane
Cell Wall
The release of energy from the food we eat
Short, hair like fibers which its primary functions are to attach itself to other surfaces
Part of a prokaryote cell that is contains circular DNA chromosomes instead of a nucleus in eukaryote cells
Bacteria move by 'swimming' with their flagella (single = flagellum)
Small, circular, double-stranded DNA molecule which is distinct from a bacteria's chromosomes. These help with anti-biotic resistance
They are feed by extracellular digestion (enzymes)
Excrete by diffusion across the cell membrane
Ecosystem
A unit containing all the organisms and their environment, interacting together in a given area
Food Chain
A chart showing the flow of energy (food) from one organism to the next beginning with a producer
Food Web
A network of interconnected food chains showing the energy flow through part of an ecosystem
Community
All the populations of the different species living in a habitat
Producer
An organism that makes its own organic nutrients
Consumer
An organism that gets its energy by feeding on other organisms
Decomposer
An organism that gets its energy from dead or waste organic matter
Population
Group of species living in the same habitat
Trophic Level
The position of an organism in a food chain or web
Habitat
Where an organism lives
If any organism becomes endangered or extinct, its entire food web will be affected, despite where it is located in the food web.
Waxy Cuticle
Copyright Bruce Chen 2018. All Rights Reserved
Waterproof layer that prevents waterloss
Upper Epidermis
Single layer of cells
few chloroplasts
transparent so it allows light through
Palisade mesophyll
top of the leaf - close to the light
lots of chloroplasts
tightly packed together
Spongy Mesophyll
Cells not packed tightly
Large surface area for gas exchange
Lots of air spaces
Guard Cell
Open and closes stomata
Stoma (s.)/ Stomata(p.)
Allows gases to enter and exit leaf
Vein
Xylem
Phloem
Sugar Transport
Water Transport
Making food using light
Using Carbon Dioxide (CO2) and Water (H2O) and through sunlight and chlorophyll turns it into glucose (C6H12O6) and oxygen (O)
Bacteria Growth
As they divide, the number of bacteria increases
A small number of bacteria begins to reproduce
The rate of division slows as resources begin to run out (Oxygen, nutrients, physical space)
Rate of bacteria death becomes higher than rate of division due to lack of resources or toxin build up
Viruses
They do not fulfil all the life processes (They do not feed, respire, excrete or grow)
Therefore most people do not consider them to be living
They only reproduce, are sensitive to target cells, and only move by being transferred
They are acellular, therefore they do not have cell membrane, cell wall etc.
Aerobic = Respiration with Oxygen
Anaerobic = Respiration without Oxygen
The chemical chlorophyll is able to capture sunlight energy
Because the leaf absorbs red and blue but reflects green, we see leaves as green
Water travels through the plant from the root to its leaves through the xylem