Biology - Organisation of Living Things - Module 2

Digestion

breakdown of large complex food molecules into small easily absorbed molecules

physical digestion

the mechanical breakdown of food

Types of physical digestion

churning of stomach, breakdown due to teeth

chemical digestion

the chemical breakdown of food by digestive enzymes

breakdown due to teeth

physical breakdown of food into smaller peices

breakdown due to saliva

saliva produced by salivary glands contains amylase enzymes that breakdown starches

digestive organs

oesophagus, stomach, small intestine, large intestine, pancreas and liver

oesophagus

transports food from mouth to stomach via muscular action called peristalsis

stomach digestion

pepsins are created here, hydrochloric acid breaks down food

small intestine

Digestive organ where most chemical digestion and absorption of food takes place

Three parts of the small intestine

duodenum, jejunum, ileum

duodenum

digests carbohydrates, lipids and proteins

jejunum

glucose, amino acids, fatty acids and glycerol are absorbed into the blood stream

ileum

absorbs nutrients

Pancreas

Regulates the level of sugar in the blood, contains enzymes allowing digestion

Gallbladder

stores bile produced by the liver

Amylase

breaks carbohydrates into simple sugars

Pepsins

breaks proteins into amino acids

Lipases

breaks fats and lipids into fatty acids and glycerol

Villi

Fingerlike extensions lining the intestinal wall that increase the surface area for absorption

liver

keeps glucose and proteins levels steady in the blood, detoxifies blood and produces bile

large intestine

Absorbs water, manufacturers vitamins A and K, creates waste

pepsin

breaks down proteins to amino acids

amylase

breaks down starch to simple sugars

lipases

breaks down fats and lips to fatty acids and glycerol

Where is amylase found?

Salivary glands, pancreas, small intestine

where is lipase found?

duodenum, pancreas

Where is pepsin found?

stomach and small intestine

unicellular organisms

single celled organisms

structure of unicellular organisms

simple, lacks organelles

colonial organisms

a group of identical single-celled organisms but do not depend on each other for survival

Multicellular organisms

Organisms made up of many different types of cells

how do colonial and unicellular organisms obtain nutrients?

diffusion

how do multi-cellular organisms obtain nutrients?

functional organisation and specialisation of cells

stem cells

unspecialised cells that have the ability to become a wide variety of specialised cells

Cell Differentiation / Specialisation

The process by which dividing cells change their functional and become specialisednon

How is the "type" of cell determined?

the location of the undifferentiated cells and the genes switched on during differentiation

flattened cells, elongated cells and folded cells

cells that have a greater SA:V ratio, allowing the efficient exchange of substances

Haemoglobin

The protein that carries oxygen in the red blood cells.

Tissues

Groups of cells with a common structure and function.

Organs

Groups of tissues that work together to perform a specific function

Systems

A group of related organs in the body

Organelles

membrane-bound structures that have specific roles in the cell

cells

basic structural and functional units of living organisms

organism

a living thing made up of many interrelated components that work together

epithelial tissue

a tissue that covers the body, protects organs and forms glands

connective tissue

A body tissue that provides support for the body and connects all of its parts, protecting them from damage

nervous tissue

body tissue is highly specialised for communication between the parts of the body

muscle tissue

A body tissue containing muscle fibres that contracts or shortens, making body parts move.

meristematic tissue

found at the tips of roots and shoots, where cells divide and produce growths

dermal tissue

Found in stems roots and leaves, the waxy layer of the plant protects it from damage and controls its interactions with the surroundings.

vascular tissue

found in the stem roots and leaves, it is responsible for transporting substances (i.e. xylem and phloem)

root system

anchors the plant, absorbing water and inorganic nutrients from the soil, usually underground

shoot system: stem

provides structural support, pathway between roots and leaves, contains dermal, vascular and ground tissue

shoot system: leaves

absorbs sunlight and carbon dioxide, produces glucose via photosynthesis

Imaging technology to determine plant structure

MRI - 3D images of plant structures
PET and NT - detail + function
micro-CT - internal structur

MRI - imaging

magnetic resonance imaging

tracing products of photosynthesis

carbon-14 - shows sunlight acting on chlorophyll
Radioisotopes - emits waves to trace the products of photosynthesis

PET - imaging

positron emission tomography

NT - imaging

neutron tomography

micro-CT

X-ray computed microtomography

body systems of vascular plants

root, shoot and vascular system

ground tissue

all internal cells in the plant other than vascular tissue

Autotroph

An organism that makes its own food

Heterotroph

organism that obtains energy from the foods it consumes; also called a consumer

vascular plants

have tissues made of cells that transport water and nutrients throughout the plant

non-vascular plants

Do not have any tissues or structures for support or to transport water and nutrients

Xylem

vascular tissue that carries water upward from the roots to every part of a plant

Phloem

Living vascular tissue that carries sugar and organic substances throughout a plant

how does water move into the roots?

osmosis

how do mineral ions move into the roots?

mostly diffusion, if the concentration gradient is too low active transport

Transpiration

the evaporation of water vapour from the leaves of plants

spongy mesophyll tissue

allows for the interchange of gases (CO2) that are needed for photosynthesis.

palisade cells

elongated cells, dense with chloroplasts they are the main photosynthetic cells in leaves

Stomata

pore-like cells which control the exchanges of gases and loss of water vapour between the plant and the outside

cellular respiration

The process by which organisms use oxygen to break down food molecules to get chemical energy for cell functions

Lenticels

opening in bark of woody stem, allows air to enter stem to provide respiration

When do stomata open?

in the light, when they become turgid

Alveoli

gas exchange surface in mammals, air sacs of the lungs where the exchange of oxygen and carbon dioxide takes place.

structure of alveoli

moist and one cell thick

How does oxygen enter blood?

oxygen diffuses from where it is concentrated in the alveoli to the less concentrated blood capillaries into the blood stream.

Respiration in fish

fish have gills that absorb the oxygen when water flows over them

Spiracles

pores on the body of insects, leading to tracheal tubes branching to tracheoles, so oxygen can enter the body

Capillarie function

blood vessels that take waste products away from tissues

vein function

carry blood to the heart

arterie function

carry oxygenated blood away from the heart to the body

Xylem structure

dead cells joined end to end with no end walls and a hole down the middle

Phloem structure

tubular-shaped, elongated, structures with the presence of walls with thin sieve tubes

Epiglottis

A flap of tissue that seals off the windpipe and prevents food from entering.

Plasma

carries nutrients

red blood cells

Blood cells that carry oxygen from the lungs to the body cells.

white blood cells

defend the body

Platelets

blood clotting cells

Aorta

main artery that carries blood away from your heart to the rest of your body.

Ventricles

Lower chambers of the heart

Atria

upper chambers of the heart

pulmonary valve

picks up oxygen to deliver to your body, prevents backflow

How big is a RBC?

7.5 micrometres long, 2.5 micrometers thick

open circulatory system

A system where the blood vessels open into spaces and not into capillaries, so that blood comes in direct contact with tissues.

closed circulatory system

A circulatory system in which the oxygen-carrying blood cells never leave the blood vessels