Biology Quiz 2
Why do cells divide
Growth, Repair (replaces worn out cells, or regenerates new tissues)
Reprouduction of asexual organisms (single celled organisms like bacteria)
chromatin
when the cell is not dividing, the DNA is un long thin strands called chromatin (looks like spaghetti)
chromosomes
when the cell is dividing, the dna coils and condenses into visible short, thick chromosomes
chromatids
each chromosome consists of two identical sister chromatids
Cell cycle
All somatic cells have a cell cycle that has two main stages, Interphase + Mitosis
interphase
cell spends most of its time in this stage, divided into three stages
G1: gap 1 - cell growth
S: synthesis of Dna - dna replication
G2: gap 2 - cell growth, preparation for mitosis
prophase
Chromatin coils up to form chromosomes, nucleolus and nuclear membrane disappear, centrioles separate and move to the poles of the cell, spindle fibres begin form, and attach to each centromere
metaphase
double stranded chromosomes line up aling the middle of the cell (metaphase plate)
anaphase
spindle fibres shorten and contract, centromeres are separated, chromosomes split into chromatids which move to the poles of the cell, each set will have a complete set of genetic information
telophase
spindle fibres disappear, nuclear membrane forms around each set of chromosomes, nucleolus appears, single stranded chromosomes uncoil into thin strands of chromatin
cytokinesis
division of the cytoplasm, happens after mitosis, splits them into two new cells, animal cells form a cleavage furrow, and plant cells form a cell plate/cell wall
regulation of the cell cycle
the cell cycle is regulated at certain checkpoints by both internal and external controls, found around G1, G2 and M phases.
apoptosis
If a cell has to many genetic errors, it will try to repair it, but if it is unable to, it will self destruct. This also may happen after a cell does too many rounds of cell division and is getting old.
cancer cells
cancer cells do not respond to checkpoints, and may stop at random points in the cell cycle, this cells divide out of control and may be damaged, they will also start to pile up on eachother
benign tumor
tumor that remains in one place in the body
malignant tumor
tumor that is capable of spreading throughout the body
tumor
abnormal lump of cells
metastasis
spread of cancer cells from the initial site to other parts of the body, they will break away from the primary tumor, and be carried through a system like the blood stream, forming a new tumor elsewhere
diagnoses of cancer
they may use blood tests, an endoscope (fibre optic cable used to view areas of the body, usually colon) X-rays, ultrasounds (uses ultra high frequency sound waves to create an image) or MRI (radio waves and a strong magnetic field are used to create a 3d image
cancer treatment
surgery (to remove tumor and cancerous tissues), chemotherapy (drugs that target cells that divide too quickly), radiation (gamma waves destroy cancerous cells dna so they cannot divide) and biophotonics (light is used to detecf and treat cancer)
specialized cells
the structure of each cell is adapted for the task/function it performs
muscle cells
long and thin structure allows cells to change in size when they contract, branching pattern that increases muscle strength, high amount of mitochondria for more energy
nerve cells
long, threadlike branches enable cells to receive and transmit signals from other cells throughout the body
red blood cells
circle with depression in centre, provides a large surface area to carry oxygen
bone cells
framework of hard material that contains minerals which provide strength and support, hold the cells together
skin cells
thin, flat layered cells form a gap free barrier to keep out potential invaders and keep in moisture
tissues
specialized cells working together to perform a function
muscle tissue
enables body parts to move, exert force, etc.
epithelial
skin, lining in the digestive tract. Covers internal and external body surfaces. Protects us from dehydration. Low friction surfaces
connective tissue
bone, tendons, blood. Strengthens and supports, or connects cells and tissues
nervous tissue
brain, nerves in sensory organs. Senses, conducts and transmits information
stem cells
a unique type of animal cell that can differentiate into many different types of cells. Make two daughter cells that develop into different types of cells depending on which parts of the dna have been switched on.
embryos
type of stem cell that may be specifically created by therapeutic cloning. Can only be obtained by destruction of the embryo, higher risk of development of tumors, unlimited growth potential
umbilical cord
type of stem cell, can turn into closely related cells like red blood cells, white blood cells, and platelets. Umbilical cord is discarded at birth, regardless of whether stem cells are harvested, limited quantities available. not as much growth potential as embryonic cells. Lower risk of cancer
certain adult tissues
stem cells like bone marrow, can regenterate but can only differentiate into their associated cell type. Difficult to obtain as they are very deep in tissues, adult patient can give permission for them to be extracted, reduced growth potential, lower cancer risk
excretory system
removes liquid wastes from the body
immune system
defends the body against infections
muscular system
works with the bones to move parts of the body
endocrine system
manufactures and releases hormones
reproductive system
includes reproductive organs
integumentary system
includes skin, hair and nails, creates waterproof barrier
nervous system
sends signals to the body
skeletal system
supports, protects, and works with muscles to move parts of the body
mouth
part of digestive system, aids in mechanical breakdown/digestion, releases enzymes for chemical digestion, releases saliva to soften food
esophogus
part of digestive system - muscular tube connecting mouth to stomach, contains smooth muscle tissue which allows it to relax and contract to move food along (peristalsis)
stomach
part of digestive system - holds and churns food, stomach lining secrets digestive enzymes and acids, smooth muscle which allows it to contract and churn ingredients
intestines
part of digestive system- between stomach and anus, secretes mucus to lubricate food, blood vessels to absorb nutrients, small intestine is 6m and most of absorbing nutrients happens, large intestine (colon) is 1.5 m and most of water is absorbed there
liver
part of digestive system - produces bile to help with digestion, detoxifies substances in the body
pancreas
part of digestive system - releases enzymes, releases insulin
gallbladder
part of digestive system - stores and releases acids to help with digestion
nose, larynx, pharynx, and trachea
nose: air goes into pharynx from nostrils
pharynx: throat, connects nose to larynx
Larynx: voicebox, connects pharnyx to trachea
trachea: windpipe, connects larynx to bronchus
bronchi
tubes that run from trachea to bronchioles
bronchioles
bronchi that lead to lungs
alveoli
tiny sacs of air that are surrounded by a network of capillaries, gas exchange between air and blood happens there
diaphragm
diaphragm is a large sheet like muscle, diaphragm pushes down when we breath in, and goes up when we breathe out
white blood cells - circulatory system
white blood cells are always looking out for disease, and will attack germs with antibodies
platlets
irregulalry shaped, colourless bodies that form clots to stop bleeding.
plasma
yellowish clear liquid that is 90% water, carries many minerals, makes up 50% of the blood's volume
the heart
made up of four different types of tissues, cardiac muscle tissue, nerve tissue, connective and epithelial tissue
arteries
blood vessels that carry blood away from the heart, are under a great amount of pressure, have thicker walls to withstand pressure, can vary in size
veins
blood vessels that carry blood towards the heart, blood is at a lower pressure, walls are not as thick as arteries, can vary in size
capillaries
small blood vessels in tissues of the body, transports blood from arteries to veins, thin walled, allows substances to diffuse between blood and other body fluids and tissues