Vascular Plants
plants that have a system which allows them to transport materials throughout the plant.
Two main types are: Gymnosperms & Angiosperms
Gymnosperms
seeds are produced in cones without fruit around them
have needles for leaves
do not produce flowers but have vascular tissues
thrive in long, cold winters and low nutrient levels in the soil.
Angiosperms
plants that produce flowers
important food source for animals including humans
can be grouped into two Classes
Monocotyledons (monocots)
dicotyledons (dicots)
monocots
seed leaves: one cotyledon
veins in leaves: usually parallel
vascular bundles in stems: scattered
flower parts: multiples of three
dicots
seed leaves: two cotyledon
veins in leaves: usually netlike
vascular bundles in stems: arranged in ring
flower parts: multiples of four or five
Cotyledon
first “leaf developed by the embryo of a seed in a plant
Vascular Tissues in Plants
There are two main types of vascular tissue:
Xylem
Pholem
These tissues are responsible for transporting needed materials throughout the plant
Xylem and Phloem are located in structures called vascular bundles. Vascular bundles are arranged differently in monocots compared to dicots
Xylem
Structure:
Hollow, thick-walled with open tapered ends
Form lon tubes when joined end to end from the root tips to shoot tips
dead when mature
Function:
Deliver water and dissolved minerals throughout the plant
Provide strength for stems and roots
Two kinds of xylem: vessel cells and tracheid cells
Phloem
Structure:
Thick walls with sieve-like ends
Alive when mature but do not have a nucleus
Form long tubes from roots to shoot tips
Function:
Deliver dissolved sugars and nutrients throughout the plant
Provide strength for stems and roots
Companion Cells Function:
Control the activity of the sieve tube cells
Transport in Xylem
Xylem transports water and dissolved minerals
Root Presuure
Roots can build up pressure that forces water upward.
Capillary Action
water is attracted to the insides of xylem cell walls (long tubular structures)
Water will cling to the tube and "climb" upwards a little due to adhesion.
Transpiration-Tension Theory (Cohesion-Tension)
water molecules in the xylem are pulled up.
Molecules of water in the xylem tubes are attracted to one another by hydrogen bonds. This is called cohesion.
Transport in Phloem
Sieve tubes must be alive to function.
Materials move up and down in the same tubes at different times
Transport can occur very rapidly (5500 g in less than one month in pumpkins.)
Lack of oxygen and low temperatures slow the transport but do not stop it completely.
Function of Roots
absorb water and dissolved minerals for plant and transport to the rest of the plant
anchor plant
storage of nutrients
Taproot
grows a long, thick, tapered root from which a few smaller secondary roots grow, (Ex: Carrot, beetroots, radishes)
Advantages:
Grows deep into soil to obtain moisture
Stores lots of nutrients in the root
Fibrous Root
grows a mass of mine roots which spread out over a wide area. Ex: grass
Advantages
Spreads over a wide area to obtain moisture and nutrients
Modified Roots
Some roots are modified to provide extra support for a plant or to store food and water.
Ex: sweet potatoes are modified to store food and water
Root Tissues
Epidermis: single layer of cells surrounds the root, stem and leaves and acts as a protective layer
Root hairs: extensions of epidermis cells which dramatically increase surface area available for water absorption
Cortex: made of large parenchyma cells which contain large vacuoles for food storage (usually starch)
​​Endodermis: layer of cells surrounding the vascular tissue in the root (allowing only water and needed dissolved minerals in)
Vascular cylinder: xylem & phloem surrounded by the endodermis
Stems
may be herbaceous (soft, green, fleshy) or woody (stiff with wood tissues).
begin as herbaceous stems.
Some develop wood tissues through growing season and become perennial, while others die and do not survive the winter (annual).
parts of a stem
Cortex: irregular cells in shape and arrangement which are general storage cells (also found in roots)
Pith: similar to cortex cells, but usually spongier because the cell walls are thinner and there are more air spaces between them
Pith cells are in the very centre region of a stem, while cortex cells surround them and vascular bundles in young stems.
Stem Adaptations
Rhizomes
horizontal underground stems that grow thin roots.
new plants can emerge from the rhizome grasses (ex: irises )
Stolons
horizontal above-ground stems.
At nodes, roots can emerge and a new plant can be formed.
(ex: Strawberry plants grow stolons and become strawberry patches.)
Tubers
Thickened areas at the end of rhizomes, are usually used for food storage. (Ex: potatoes)
Potato tubers on the roots of a potato plant
Corms
Thickened stems which remain underground. Resemble bulbs in shape
(bulbs are underground leaves not stems)
Leaf Tissues
Cuticle: a waxy layer on the surfaces of the leaf which prevents excess water loss
Epidermis: small, colourless cells on the surfaces of the leaves which manufacture cuticle and are a protective layer
Mesophyll: cells specialized for photosynthesis
Two types: palisade- arranged in tight tow
sponge- air spaces between
Vein: contains the vascular tissue (xylem and phloem)
(a vascular bundle in a lead is a vein)
Guard Cells
pair of guard cells are attached together at both ends.
when water enters the guard cells, forces the cells to buckle outwards creating the stoma opening.
When water leaves the guard cells, they become flaccid and the stoma close. (this occurs when it gets too dark for photosynthesis or when there is not enough water)
In general, stomata are open in the day and closed at night, also close during very dry, hot conditions
reproduction in plants
flower is the reproductive structure of plants.
flowers have both male and female reproductive structures.
male gametes (sex cells) are located in the pollen grains
egg cells are located in the ovary of the flower.
Fertilization (pollination) of plants occurs when the pollen grains reach the egg cells.
stamen
When pollination happens, pollen is produced by the male part of the flower, called the stamen.
The end of the stamen is called the anther, and that's where pollen is made.
Pollen contains the genetic information.
Sexual Reproduction in plants
Fertilization is when this pollen travels down the pistil of the flower and reaches the egg cells in the ovary (which also contain genetic information).
When the DNA combines, seeds are produced.
Flowers can cross-pollinate or self-pollinate.
Asexual Reproduction
only one parent is needed, and the copies that are made are genetically identical.
Plant cuttings can be used to propagate plants, and is called vegetative propagation.
In grafting, one plant can be combined with another.
a part of a plant is attached to another plant (with its own root system).
A new plant grows as a combination of the two - the introduced plant part can now use the root system of the other plant.
Reproductive System of an Angiosperm
A. Anther: pollen is stored and produced
B. Pollen Grains: cases containing male gametes
C. Stigma: sticky “lip: of pistil that collects pollen grains
D. Style: stalk that supports stigma
E. Ovary: swollen base of pistils, contains ovules
F. Ovules: sacs containing female gametes
filament: stalk that supports anther
Tropism
growth of a plant toward or away from a stimulus
Thigmotropism
growth of a plant toward or away from touch (ex: grape tendrils grow around wires
Geotropism (gravitropism)
Growth of a plant in response to gravitational pull (eg: roots grow toward gravitational pull but stems grow away)
Hydrotropism
Growth of a plant in response to moisture (eg: roots grow toward source of moisture in the soil)
phototropism
Growth of a plant in response to light (eg: growth of plant leaves and stems to angle toward the light)
Nastic Movements
plant responses to stimuli hat are independent of direction.
response is quick and reversible, but not growth-related
eg: the venus fly trap quickly closes its leaves to capture an insect, mimosa leaves immediately droop when touched
Plant Hormones (Growth Regulators)
Auxins:
promote elongation of cells
stimulate root growth & ripening of fruit
Gibberellins:
promote cell division and elongation
cause enlargement of fruits
Cytokinins:
stimulate cell division and leaf growth
cut flowers sprayed with cytokinins extend their shelf life
Abscisic Acid:
inhibits growth
causes dormancy of seeds
causes the closing of stomata
Ethylene:
gas which stimulates fruit ripening
involved with colour changes and softening of fruit as it ripens
Crop Rotation
different crops are planted each year or fields are left to lie fallow (rest)
Circulatory System Organs & Function
Heart
To distribute blood and other nutrients to all your body’s organs and tissues.
Digestive System Organs & Function
esophagus, stomach, pancreas, liver, gallbladder, small intestine, large intestine and anus
digest and absorb food and then excrete the waste product
Respiratory System Organs & Function
pharynx, larynx, trachea, bronchi and lungs
move fresh air into your body while removing waste gases
Excretory System Organs & Function
kidney, bladder, ureter, urethra, large intestine, liver, lung, skin
remove wastes from the body.
Muscular System Organs & Function
heart, digestive organs
Responsible for movement
Endocrine System Organs & Function
Pancreas, ovaries, testicles
coordinate your metabolism, growth, and development, and release hormones into the bloodstream.
Reproductive System Organs & Function
Women: ovaries, fallopian tubes, uterus, cervix, and vagina
Men: penis, testes and the scrotum
To produce egg and sperm cells.
Integumentary System Organs & Function
skin
protecting your body from bacteria, infection and injury
Nervous System Organs & Function
Brain, spinal cord,
sends messages back and forth between the brain and the body. The brain is what controls all the body's functions.
Skeletal System Organs & Function
Supports body movement and protects internal organs
goal of digestive system
digest our food and absorb molecules to provide nutrients and energy
Filter Feeding
filter food from large quantities of water.
Fluid Feeding
obtain their food from removing fluids from other organisms.
Gastrovascular Cavity
a tube with only one opening; food and waste enter/exit the same opening ex: jelly fish
Alimentary Canal
two openings; food enters one opening (mouth) and waste exits the other (anus) ex: earth worm
Mechanical Digestion
physical breakdown/movement of foods into smaller pieces (primarily carried out by the mouth and teeth)
Chemical Digestion
breakdown of food through chemicals (acids and enzymes) starting with saliva in the mouth
stages of digestion
Ingestion - the taking in of nutrients;
Digestion - the breakdown of food into smaller subunits;
Absorption - the transfer of the digested nutrients into the bloodstream; and
Egestion - the removal of waste products of digestion from the body.
Mouth
Site of mechanical digestion
Includes teeth, tongue, and saliva
Teeth: tear, cut, and mash food to break food down into smaller pieces
Tongue- moves food over teeth and has taste buds for tasting
Saliva- this starts before food even enters our mouth-salivary glands produce saliva which contains an amylase enzyme that digests starch into maltose (beginning of chemical digestion)
Esophagus
Bolus of food travels down the pharynx into the esophagus
The esophagus secretes mucin which lubricates it
Bolus moves down the esophagus through peristalsis
stomach
Muscular storage sac for food
Cardiac sphincter- controls entry of materials in and out of stomach
Rugae- ridges on inner lining of stomach that help with mixing of food
Muscles work together to mix and churn food with digestive juices
Pyloric sphincter- circular valve at base of stomach that controls exit of materials
gastric juices in the stomach
hydrochloric acid (HCI): kills microorganisms in our food and helps with further chemical digestion
pepsin - enzyme that begins protein digestion
mucus- this slimy secretion is produced by the stomach lining cells to protect the stomach itself from the gastric juices
Small Intestine
The chyme ( partially digested food) enters the small intestine from the stomach.
three main sections of small intestine
duodenum - 25-30 cm long
jejunum - 300 cm long
ileum - 400 cm long
duodenum
majority of chemical digestion occurs here using enzymes secreted by the pancreas and by glands in the wall of the intestine
jejunum
chemical digestion is completed here and some absorption occurs
ileum
absorption mainly occurs here
Large Intestine (colon)
1.5 m long with 4 main sections: ascending colon, transverse colon, descending colon and sigmoid colon.
rectum stores solid waste temporarily.
anus is a sphincter valve.
caecum is a blind end sac where small intestine leads into the colon
appendix is a tiny extension from the caecum (can become infected easily and has to be removed)
main functions of the colon
Recover water into the bloodstream and form solid feces.
Form/absorb certain vitamins (eg. Vitamin K & B)
Liver
main function is to produce bile.
Bile is an emulsifying agent which helps to spread fats over a wide surface
Bile is transported through the hepatic duct.
Gallbladder
storage sac which holds bile from the liver.
bile salts can crystalize and form "stones" -called gallstones - which can block the bile duct.
Pancreas
produces a variety of digestive enzymes and secretes them through the pancreatic duct into the duodenum.
functions of the circulatory system:
transport oxygen and carbon dioxide
distribute nutrients and transport metabolic wastes
help maintain the body temperature
circulate hormones
Transport in Unicellular Organisms
do not require a specialized transport system
entire cell has access to the surrounding environment.
"streaming" (moving cytoplasm) allows substances to be distributed throughout the cell.
Transport in Small Multicellular Organisms
do not require a specialized transport system.
fluid is taken in through the mouth and enters a body cavity that extends through most of the organism.
materials are exchanged directly between the fluid and individual cells of the organism
Transport in Larger Multicellular Organisms
Substances are unable to diffuse or access all body cells quickly enough
two types of circulation systems
Open Transport Systems
Closed Transport Systems
Open Transport Systems
Open system “hearts” are weak
Blood does NOT stay in blood vessels but fills a body cavity
Blood travels very slowly, and “sloshes around in the cavity
Typically found in insects, where blood does not distribute oxygen to body tissues
Nutrients in blood directly surround body cells and diffuse into cells
Closed Transport Systems
closed system hearts pump blood strongly
blood remains in blood vessels at all times
nutrients in blood diffuse into the extracellular fluid where they are diffused into the cells
Types of Blood Vessels
Arteries: Carry blood away from the heart
Veins: Carry blood into the heart
Capillaries: Connect arteries to veins, gas exchange drops off O2, picks up CO2
Pathway of Blood
Lungs pick up oxygen
Pulmonary Vein into the heart
Through the Left Atrium and Ventricle pumped to the body
Aorta-major artery out of heart
Arteries path through the body
Capillaries destination of oxygen, and carbon dioxide is picked up
Veins take deoxygenated blood back to the heart
Vena Cava's "blue" blood enters the heart
Through the Right Atrium and Ventricle pumped to the lungs
Pulmonary Artery "blue" blood heads to lungs
Lungs-Drops off carbon dioxide
Plasma
accounts for 55% of the blood volume
92% is water
7% are other blood proteins
1% are other nutrients and ions
Red Blood Cells (RBCs)
Make up 44% of the total volume of blood
Have no nucleus
Main Role → Transport oxygen/CO2
RBCs contain the molecule hemoglobin (which gives red colour)
Oxygenated blood is bright red, deoxygenated blood is dark red.
White Blood Cells
Makeup about 1% of blood volume
This amount almost doubles when the body fights infection
Leukocytes have a major role in the immune response
have a nucleus and are colourless.
Platelets
make up a very small portion of the blood.
fragments of previously existing cells and break down quickly in the blood.
No nucleus and lasts a week to ten days
Their role in the blood is to aid in the blood clotting process.
Blood-Clotting
Blood vessel breaks and sends out a signal.
Platelets are attracted to the site of injury.
Platelets then rupture and release more chemicals.
Other agents will form certain enzymes and end with fibrin (from fibrinogen).
Fibrin forms a mesh of strands around the injury that trap blood cells and form a clot.
Tissues
a collection of similar cells that group together to perform a specialized function.
Gas Exchange
The basic functions of the respiratory (gas-exchange) system are to:
Provide each cell with O2
Allow each cell to eliminate CO2
Cellular respiration
The process where energy-containing molecules are broken down to release energy in a form the cell can use (ATP). Requires oxygen, forms carbon dioxide waste.
Gas Exchange
Cells take in oxygen and release carbon dioxide.
Breathing
The process of inhalation and exhalation - moving volumes of air into or out of the lungs.
Diffusion
used to move particles from an area of higher concentration to an area of lower concentration.
Site of Gas Exchange in Humans
Alveoli
Air Pathway: Starts from the mouth and nose.
Trachea (Windpipe): Air moves down through it.
Bronchi: Trachea divides into the right and left bronchi.
Bronchioles: Bronchi further divide into smaller branches called bronchioles.
Alveoli: Bronchioles terminate at alveoli.
Gas Exchange: Occurs at the alveoli.
Upper Respiratory Tract
Nasal Cavity- consists of nasal hairs, mucus, and blood vessels
Nasal hairs-trap dust and dirt to protect delicate lung tissue
Mucus- traps dirt and dust AND moistens the air to prevent the Jung tissue from dying (which will help diffusion occur quickly)
Blood Vessels- warm the air (diffusion is faster in warm air than in cold air)
Uvula-a flap of tissue hanging at the back of the mouth which closes when swallowing to prevent food and liquid from entering the nasal cavity
pharynx: the "throat" - an area where air and/or food & water pass
epiglottis: The flap of tissue which folds over the trachea when swallowing to prevent materials from entering the air passageways.
Lower Respiratory Tract
Larynx ("Voice Box"):
Consists of two bands of tissue stretched across the opening of the trachea.
Muscles Contract: Bring bands close together.
Air Passing: Causes bands to vibrate, producing sound.
Relaxed: Low sounds.
Tightened: High sounds.
Alveoli: where gas exchange occurs
Lungs:
Humans have 2 lungs: one on the left and one on the right
The right lung has three lobes.
The left lung has two lobes.
Each lobe is divided into lobules, each with its own bronchiole.
ventilation
Definition: The process of air moving into the lungs and reaching the alveoli.
Breathing: a pressure differential must occur, air moves from an area of high pressure to low pressure.
Inhalation: pressure in lungs must be less than outside atmosphere.
Exhalation: pressure in lungs must be greater than outside atmosphere.
Mechanical Ventilation: Achieved by muscle contractions and relaxation. (muscles involved: Diaphragm and Intercostal Muscles)
genetics
the branch of biology dealing with the principles of variation and inheritance in organisms
Mendelian Genetics
refers to how traits are passed from parents to offspring
dominant
characteristics that are always expressed in an individual
recessive
characteristics that are latent (present but inactive) in an individual
heterozygousÂ
an individual who has two different alleles for a gene (ex: a girl has one dark allele and one blonde allele)
alleles
one form of a gene (usually two types for a gene)
(ex:Dark hair allele and blond allele)