Biology Unit 1 Complete

8 Life Processes

• Movement

• Respiration

• Sensitivity

• Control

• Growth

• Reproduction

• Excretion

• Nutrition

Movement

An action caused by an organism causing a change in place or position.

• Animals: locomotion

• for food and water

• to move away from predators

• Plants: change their orientation

  • positive phototrophism

  • positive geotrophism

Respiration

Chemical reaction carried out by all living organisms to release energy from glucose in the form of ATP.

• Aerobic (with oxygen)

• Anaerobic (without oxygen)

Sensitivity

The ability to respond/react to stimuli in the surroundings

• Animals: nervous system, endocrine system

• Plants: phototropism, geotropism

Homeostasis

Controlling internal environments to keep conditions within required limits

Humans:

• Thermoregulation

• Osmoregulation

• Glucoregulation

Plants:

• Transpiration: to maintain suitable temperature

Growth

A permanent increase in size by changing the mass or number of cells

• Animals: grows larger between the zygote and adult stage with change in proportion or shape

• Plants: grows larger throughout its life with new shoots, leaves, branches, etc. forming each year

Reproduction

Process that leads to the production of more of the same kind or organism

Types:

• Asexual

• Sexual

Excretion

Removal of toxic waste products in excess of requirements

Animals

• CO₂ from respiration

• Water from respiration

• Urea (contains Nitrogen) from the breakdown of proteins

Plants

• O₂ from photosynthesis

• CO₂ from respiration

• Water from respiration and other chemical reactions

Nutrition

Organisms must obtain food to provide energy through feeding or photosynthesis

Animals

• consume other living organisms to obtain required energy

• break down larger complex molecules into simpler molecules through digestion

Plants

• use sunlight, CO₂ and H₂O to produce O₂ and glucose in the process of photosynthesis

Bacteria

• Prokaryotes

• Microscopic

• Unicellular

• Cell wall: Peptidoglycan

• Cell membrane

• Cytoplasm

• Plasmids

• No nucleus: circular chromosome of DNA

• Some photosynthesise (no chloroplasts but have chlorophyll-like substances and sugar-digesting enzymes), but most are heterotrophs, some are saprotrophs

• Eg: Lactobacillus bulgaricus, Pneumococcus

Viruses

• Not considered alive

• Don't carry out 8 life processes

• Only reproduce inside a host's metabolic pathways

• Smaller than bacteria

• Parasitic

• Infect every type of living organism

• No cellular structure: protein coat and only one type of nucleic acid (RNA or DNA)

• Ex: TMV, HIV, Influenza

TMV

Tobacco Mosaic Virus

• First virus to be isolated by scientists

• Infects about 150 species of plants, including tomatoes and cucumbers

Symptoms

• Causes a distinctive pattern of discolouration since it affects chloroplasts

• Plant won't grow- lack of photosynthesis- reduces yield

Spread

• Spread by direct contact

• Stays in soil for 50 years

Cure

• No treatment

• Method of control: good hygiene

• Farmers use TMV-resistant crop variants

Main Eukaryote Kingdoms

• Plants

• Animals

• Fungi

• Protoctists

Plants

• eukaryotes

• multicellular

• cellulose cell walls

• chloroplasts: can photosynthesise

• store carbohydrates as starch or sucrose

• ex: flowering plants, legumes, cereals

• no nervous coordination

Animals

• eukaryotes

• multicellular

• no chloroplasts: no photosynthesis

• no cell walls

• nervous coordination and locomotion

• store carbohydrates as glycogen

• ex: mammals and insects

Fungi

• eukaryotes

• mostly multicellular but some unicellular

• made of mycelium consisting of hyphae

• chitinous cell walls

• feed by secreting enzymes onto decaying organic matter, then absorb the digested molecules → Saprotrophism

• some are parasitic and feed on living material

• store carbohydrates as glycogen

• ex: Mucor, Yeast, Athlete’s Foot, Ringworm

Protoctists

• different from other 3 types of eukaryotes

• unicellular and multicellular, but sometimes aggregate to form colonies

• some are more like animals → Amoeba

• some are more like plants (cell walls and chloroplasts) → Chlorella

• pathogen → Plasmodium

• some are autotrophs, others are heterotrophs

Influenza

3 different Influenza viruses infect humans to cause the flu

• A, B, C infect the cells that line airways

• cause high temperature, body aches, fatigue

• A causes most cases of the flu globally

HIV

HIV can lead to AIDS

Symptoms

• starts with flu-like illness

• can stay hidden for many years until the immune system can no longer deal with other infections or cancers → late stage HIV (AIDS)

Spread

• direct sexual contact

• exchange of bodily fluids, like blood, when needles are shared

• from mother to child during birth or in breast milk

Cure

• no cure

• antiretroviral drugs used early can effectively slow/halt the progress to AIDS