viruses+domains

what are virues

tiny, non cellular structures

Effect of viral disease among crops and animals on farms

Leads to loss of crop yield and livestock, increased control and prevention costs, reduced farm productivity, resulting in significant economic losses.

living features of viruses

contain genetic material
have protein coat (capsid)
can replicate

non living features of viruses

non cellular
cant carry out metabolism independenly
require a host cell to replicate

structure of viruses

core of nucleic acid
protein coat (capsid) on surface

how do differentiate viruses

shape (round rod or complex) type of nucleic acid

bacteriophage

virus that infects bacterial cells

5 stages of virus replication

1. Attachment- Proteins on the virus attach to special receptors in host cell

2. Entry- Forms a hole in host cell and nucleic acid is inserted into host cell

3. Synthesis- Host cell nucleic acid inactivated. Virus uses hosts organelles to produce copies of viral proteins and viral DNA or RNA

4. Assembly- new viruses assembled

5. Release- new viruses released by lysis of the host cell

Disadvantages of viruses

human disease (AIDS)
plant disease (tobacco mosaic disease)
animal disease (foot and mouth)
economically - disease in crops

advantages of viruses

genetic engineering (used as vectors to carry genes)
infection control (infection control - bacteriophages can be used to control infections)
biological control

antibiotic def

Chemical produced by microorganism that stops the growth of or kills other microorganisms without damaging human tissue

why dont antibiotics work against viruses

• target structures found in bacteria (eg cell wall, ribosomes)

• viruses dont have these structures, and reproduce using the host structures

• therefore antibiotics are inffective against viruses

whats wrong w using antibiotics for a viral infections

can contribute to antibiotic resistance, where bacteria evolve and become more difficult to treat

what is phylogeny

study of evolutionary relationships between organisms

how does phylogeny classify organisms

based on shared ancestry

how do scientists if organisms have common ancestors

• structural features (skeleton, body shape)

• biochemical evidence (proteins enzymes)

• genetic evidence

how do scienctists use dna/genetic evidence to see if organisms have common ancestors

• closely related species have more similar dna sequences

• dna evidence is the most reliable because its not influenced by environmental factors

• organisms that are more closely related will have more similarities in the sequence of their dna

importance of phylogeny

• reflects evolutionary history

• more accurate than classification based on appearance

• helps scientists understand how species evolved and how closely related they are

what are phylogenetic trees

• branched diagram representing evolutionary relationships among organisms

use of phylogenic tree

shows how a species or other group evolved from a shared ancestor

what does the root of a phylogenetic tree show

represents common ancestor of all organisms in the tree

what do branches on a phylogenetic tree rep

number of ancestors evolved from a root or node

whats a node in a phylogenetic tree

(branch point) point where branch splits into two or more lineages (species with the most recent node are more closely related)

species less related have what in the phylogenetic tree

common ancestor further to the left/back in time

how do i know if a species has gone extinct

if the group doesnt reach present day

whats a clade

group of organisms that includes a common ancestor and ALL of its descendents

whats a taxon

any named group of organisms at any level of classification

whats a species

group of organisms that can interbreed to produce fertile offspring

what are the three domains

bacteria, eukarya and archaea

bacteria kingdom(s)

eubacteria

eukarya kingdom(s)

animal

protist

plant

fungi

archaea kingdom(s)

archae

taxonomy

study of classifying organisms based on shared characteristics

what is classification

when organisms are arranged into groups based on similarities and differences

whats the benefit of classifying an organism in greater detail

allows scientists to understand them more precisely and understand their relationships

importance of classification in bio

• allows scientist to understand evolutionary relationships

• enables scientists to study and compare organisms with ease

• worldwide scientists can communicate clearly using common system

What is meant by the binomial nomenclature

Universal system used to name organisms

Why is binomial naming system used instead of common names

To avoid confusion caused by common names, which can vary between languages and regions

Two parts of sceintific name

Species and genus

Two rules that must be followed for binomial naming system

Species in capital and genus in lowercase
Written in italics, if handwritten underline

Why is the binomial naming system described as a universal system?

Used worldwide regardless of language

Two organisms have the same genus name but different species names. What does this tell us about their evolutionary relationship?

They are closely related and share recent common ancestor