Biology Flashcards
What are the 3 stages of the cell cycle?
Interphase
Mitosis
Cytokinesis
What happens during interphase?
During interphase the cell carries out all life activities except division
What do the DNA material look like?
Very long invisible strands
When the cells prepare for division in interphase, what happens to the DNA strands?
The strands are duplicated and more organelles are formed.
What is mitosis?
The division of the contents of the nucleus (DNA)
What is cytokinesis?
The division of the rest of the cell (ie. cytoplasm etc.) each cell division produces 2 genetically identical cells called daughter cells.
What are the 4 phases of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What happens in prophase?
- Copied DNA strands condense into visible chromosomes
- the 2 identical DNA strands (chromatids) are held together by a centromere
- nuclear membrane dissolves, nucleus disappears
- centrioles move to opposite ends of the cell forming spindle fibres between them
What happens in metaphase?
Chromosomes line up along the middle of the cell and attach to spindle fibres by the centromere
What is anaphase?
Centromere splits and the sister chromatids separate (now called “daughter chromosomes”)
Spindle fibres retract pulling the two daughter chromosomes to opposite ends of the cell
What is telophase?
Chromosomes reach opposite poles of the cell and start to unwind to become less visible
-spindle fibres break down and new nuclear membranes form
What happens in cytokinesis?
Division of cytoplasm to complete the creation of two new daughter cells
- an indentation forms and pinches the cell into two cells
- daughter cells are genetically identical
- in plant cells a cell plate forms between the daughter cells that will form a new cell wall
- in animal cells the cell membrane and cytoplasm pinch inward (forming a cleavage furrow) at the middle separating the two cells
Give an example of an individual cell
A heart muscle cell
What are the levels of cell organization within each organism?
- An individual cell
- Tissue
- Organs
- Organ systems
What is tissue?
A group of similar cells that share the same structure and function
What are the 4 major types of tissue in animals?
Epithelial
Connective
Muscle
Nerve
What is an organ?
- A combination of several types of tissue working together to preform a certain function
- has connective, nerve and muscle tissue
- most organs are only involved in one function (ex. Pancreas -> digestion and also the endocrine (hormonal) system)
What is an organ system?
A group of organs working together to preform a vital body function ex. circulatory system (heart, blood vessels, blood)
-some systems are interconnected ex. circulatory, respiratory and urinary
What is an organism?
All the organ systems working together to allow a plant or animal to carry out life functions
What are the 2 types of stem cells?
Embryonic and tissue
What is an embryonic stem cell?
Can differentiate into any kind of cell
-found in very young embryos (less than a week old)
What are the 3 principals of cell theory?
- All living things are made of cells
- The cell is the simplest unit of all life
- All cells come from other cells
What are prokaryotes?
- the simplest cells
- lack a nucleus and other advanced cell parts
- single felled bacteria are considered a prokaryotic cell
What are eukaryotes?
- eukaryotic cells can exist as single celled organisms or multi cellular organisms
- have more complex internal organization including a nucleus etc.
- protists, fungi, plants and animals have eukaryotic cells
What is muscle?
Made up of long cells that are able to contract.
What is nerve?
Cells are long and thin with a long axon
What is the digestive tract?
Lined with epithelial tissue (like skin) and has many goblets, cells to produce mucus, to allow for the smooth transport of food and protection from digestive enzymes
What is the mouth?
Breaks down food mechanically with the use of teeth and tongue and chemically using enzymes to break large molecules to smaller ones
What is saliva?
A mixture of water, mucus and enzymes which help with the processing of food
What is the esophagus?
- Muscular tube that connects the mouth to the stomach
- made of smooth muscle tissue that contracts to push down food
- can contract and relax with conscious thought
- controlled by nerve tissue
What is the stomach?
Muscular pouch which is designed to hold food and churn it with various digestive juices
- epithelial tissue lines the stomach and secrets digestive enzymes and hydrochloride acid to chemically break down food and mucus to protect the stomach from gastric juices
What is the small intestine?
- A long tube that uses smooth muscles to push down food using mostly enzymes
- when nutrient molecules are small enough they are absorbed into the bloodstream
- once in the bloodstream the small nutrients are delivered to the cells
What is the large intestine?
- materials entering this shorter portion of the intestine are mostly waste
- water and fluids are absorbed from the waste and it is eventually released from the anus
What are the accessory organs in the digestive system?
The liver, pancreas and gall bladder add digestive enzymes and fluids
What is bile?
Created by the liver, helps break down fats
What is insulin?
Controls blood sugar, released by that pancreas
What is the circulatory system made up of in humans?
Blood, blood vessels and the heart
What is the function of the circulatory system?
To transport substances around the body including
- Nutrients from the intestines to all cells
- O2 from the lungs to all cells
- Wastes from cells to areas of disposal
- CO2 from cells to lungs to be exhaled
What are the 4 components of blood?
Red blood cells
White blood cells
Platelets
Plasma
What are red blood cells?
Make up almost half of the bloods volume
-Contain the red pigment, hemoglobin which allows the transport of O2 through the body
What are white blood cells?
- Make up less than 1% of blood but are very important in fighting infection
- recognize and destroy foreign bacteria and viruses
What are platelets?
Tiny cells that helps in blood clotting when small blood vessels are torn
-make up less than 1% of blood
What is plasma?
- A protein rich, clear yellowish liquid that carries blood cells along
- Makes up more than half of the bloods volume.
What are blood vessels?
Form a network of tubes to transport blood to and from all cells
What are the 3 main types of blood vessels?
- Arteries
- Veins
- Capillaries
What are arteries?
- Carry oxygenated blood away from the heart and towards the tissues
- have thick, muscular walls to allow blood to be carried under very high pressure
What are veins?
- Carry deoxygenated blood toward the heart and from the tissue
- the walls are thinner since blood from the tissue is under less pressure
What are the capillaries?
- link together arteries and veins
- very small
- have very thin walls to allow for diffusion of nutrients and gases across tissues
What are the 3 types of tissue?
- Cardiac muscle
- Connective/tendons and blood in the heart
- Nerve/regulates heart rate
Why does spikey hail tissue line the heart?
To reduce friction and allow blood to flow easily
What is the respiratory system?
Provides the body with O2 and rids the body of waste CO2
What is the trachea?
A tube that is supported by rings of cartilage which keep the trachea open for east transport if air
What is the respiratory tract?
- Lined with epithelial cells which are covered in hair like cilia and other cells which secrete mucus to line the tubes
- together the mucus and cilia help moisten and filter the air to prevent dirt, dust and particles from reaching the lungs
What are the bronchi?
Branches into the right bronchus and left bronchus and left bronchus which are designed to carry air to the lungs
What is the alveoli?
In the alveoli O2 and CO2 are exchanged in the blood, since each alveolus is syringed by it’s own capillary
- transfer of gas that occurs by diffusion across cell membranes
Explain how breathing is involuntary
The brain detects CO2 levels in the blood and signals muscles to contract
What is the musculoskeletal system?
- Made up of bones and skeletal muscles
- supports the body, protects organs and allows for movement
What is bone?
- hard and dense
- canals inside the bones contain nerves and blood vessels
- only a small percentage of bone tissue is actually living
- some contain marrow which produces red and white blood cells and stem cells
What is the skeleton?
- main role is to provide structure and support for the body and allow muscles to attach for movement
- store calcium and minerals
- some bones protect soft organs
What are ligaments
Tough elastic tissues that connect bones together at joints and are mostly made of long collagen fibres
What are tendons?
Similar to ligaments but less elastic and connect to bones and muscles
What is cartilage?
A dense tissue found in the ear, nose and between the vertebrae and in joints and provides support for bones and other tissues to prevent damage
What are muscles?
- attached to the skeleton to help it move
- bundles of long muscle fibres containing specialized proteins that cause muscles to contract
- contract when the nerve cells signal
How do muscles work?
The nervous system sends a signal, muscles contract and exert a force on the bones they’re connected to
What are the 3 types of muscle?
- skeletal(voluntary)
- smooth(involuntary)
- cardiac
What is the nervous system?
- like a communication network
- made up of the brain, the spinal chords and the peripheral nerves
- senses the environment and coordinates appropriate responses
What are the 2 main parts of the nervous system?
The central nervous system and the peripheral nervous system (PNS)
What is the central nervous system?
- consists of the brain and spinal chord, both are surrounded by cerebrospinal fluid which cushions the delicate organs and transports chemicals as well as removes waste
- Protects the brain and the vertebrae protect the spinal chord
- the brain receives information from all the sensory organs via the spinal chord
- it contains centres for conscious thought and memory
- allows us to interpret information and make decisions
- spinal chord transfers information to and from the brain
What is the peripheral nervous system
Consists of all nerves extending beyond the brain and spinal chord
- it relays information about the internal and external environments to the brain and carries messages back from the brain to other organs
What are the 3 types of nerves in the peripheral nervous system?
- Nerves that control computers muscles
- Nerves that carry information to and from specialized neurone called sensory receptors, found in eyes, ears, taste buds and touch receptors
- Nerves that regulate involuntary functions ex. Digestion breathing heartbeat
What is nerve tissue?
- makes up the brain spinal chord and peripheral nerves
- there are 100 billion neurons in the brain
- neurons do not regenerate well when damaged
- nerves are bundles of neurons surrounded by connective tissue
What do neurons consist of?
A cell body, many short extensions called dendrites and one long extension called and axon. impulses travel through dendrites to the cell body and then along the axon before jumping to the next neuron or to a muscle.
