1 Intro to biology

Key Concepts

• The study of life reveals common themes.

• The Core Theme: Evolution accounts for the unity and diversity of life.

• In studying nature, scientists make observations and then form and test hypotheses.

• Science benefits from a cooperative approach and diverse viewpoints

Overview inquiring about life

An organism’s environmental adaptations result from evolution – The seed cones of lodgepole pine are adapted to allow rapid regrowth after a fire (Jack Pine in Cape Breton) 

 • **Evolution**- process of change that continuously transforms life on Earth 

Form fits function 

The form of something looks like what it is meant to do 

(eagles talons are not made for swimming and ducks aren't meant for grabbing animals 

Themes in the study of life

Describe the properties of living organisms? They have cells, they respire, they con energy, maintain homeostasis, reproduction, nutrition 

Order, Energy processing, evolutionary adaptation, regulation, growth and development, response to the environment, reproduction 

Emergent properties

**Emergent Properties**- emerge from the arrangement and interactions of parts within a system 

Emergent properties are not unique to life 

For example, a box of bicycle parts will not take you anywhere 

Assembled correctly they can pedal you almost everywhere 

 "the whole is greater than the sum of its parts"- aristotle if you have all the parts of a bike in front of you its still not a bike 

The Power and Limitations of Reductionism 

The Power and Limitations of Reductionism 

**Reductionism**- reduction of complex systems to simpler components 

Powerful strategu in biology, as the study of individual componenets is more manageable 

For example, studying molecular structure of DNA helps to understand inheritance

Systems Biology (1 of 2)

 • Understanding biology requires a balance of **reductionism** with the study of **emergent** properties 

 • Emergent properties are explored using systems biology, which studies interactions among parts of a biological system  

• **Systems biology** constructs models for dynamic behavior of biological systems  

 

The systems approach poses questions such as 

 – How does a drug for blood pressure affect other organs? 

 – How does increasing CO2 alter the biosphere? 

investigating all possible outcomes

Structure and Function are Correlated at all Levels of Biological Organization 

Structure and Function are Correlated at all Levels of Biological Organization 

 • Structure and function of living organisms are closely related 

 – For example, a leaf is thin and flat, maximizing the capture of light by chloroplasts 

What about conifers? Much smaller needles much less susceptible to dehydration 

The Cell: an Organism’s Basic Unit of Structure and Function

The Cell: an Organism’s Basic Unit of Structure and Function • The cell is the lowest level of organization that can perform all activities required for life  

Viruses – are they alive? NO they are cell like but are not cells one reason why is they cannot live on their own 

Introduction: Themes in the Study of Life   cells

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• What do you think is in common between all cells? 

What would you answer?  

\*\*\*\*Why are they called cells? Robert Hooke - 1665   he was looking at cork cells like from a wine bottle and he sees a lot of square/ rectangular cells (they are essentially dead plant cells) it reminds him of the rooms tjat the munks live in (they live in small SQUARES rooms NOT JAIL CELLS!!) 

Who used the term “cells”?  

Forms of Cells 

**All cells**- are enclosed by a membrane, use DNA as their genetic information 

**Eukaryotic cell**- has membrane enclosed organelles (largest is usually the nucleus) HAVE A TRUE NUCLEUS 

**Prokaryotic cell** is much simpler, usually smaller, and does not contain membrane-enclosed organelles  NO NUCLEUS but have a NUCLEAR MEMBRANE 

Pro karyote (before nucleus)    Eu karyote (true nucleus) 

Karyo.. Nucleus (Latin) kernal (Greek)   

Who came first? Prokaryotes because they are more simpler 

Theme: Life’s Processes Involve the Expression and Transmission of Genetic Information 

• Chromosomes contain most of a cell’s genetic material as **DNA** (deoxyribonucleic acid)

Ribo (or ribose) ose=sugar   nucleic   found in nucleus or nucleic region    acid-phosphate groups gives it acidic properties     deoxy- there is one less oxygen in deoxyribonucleic acid than ribonucleic acid   which is why it is so long lasting and it allows it to_____     DNA is only not lasting in bleach and sunlight it is broken down fairly quickly in those

DNA is the genetic material

• Ability of cells to divide is basis of all reproduction, growth, and repair of multicellular organisms

• Each chromosome has one long DNA molecule with hundreds or thousands of genes  

• **Genes** encode information for building the molecules synthesized within cells  

Why chromosome? What does that word mean?  

if you grow them in the right media they show up in different colors 

Chromo-color   some-body

DNA Structure and Function (1 of 3) 

 • DNA is inherited by offspring from their parents  

• DNA controls the development and maintenance of organism 

DNA is in the mitochondrial DNA is from the mother because only the egg has mitochondrial DNA 

The reason that it exists was that instead of a big cell eating a mitochondria it started to make it inside?? 

Each DNA molecule is made of two long chains arranged in a double helix • Each chain is made up of four kinds of chemical building blocks called nucleotides that are nicknamed A, G, C and T 

DNA is very stable why? Ex?   if you heat up DNA it renatures but most other proteins cant renature once it is renatured (if you crack an egg and cook it but then there is a  

Gene Expression (1 of 2) 

 • Genes control protein production indirectly  

• DNA is transcribed into RNA, which is then translated into a protein  

• Gene expression - process of converting information from gene to cellular product  

**Transcription** (process where in our cells a DNA(serves as a template) molecule gets transcribed to make an RNA molecule this takes place inside the nucleus) 

**Translation** (takes place outside of the nucleus, at the ribosomes either on the endoplasmic reticulum or floating around)   

**Intron** 

 **Exons** 

 **Splicing** 

Genes are the parts of our DNA that are expressed (not necessarily seen) that send out critical information for an organism  

Think of it like there is 10 0000 words and 10 are in the sentence or something like that 

analogy and extra info

If you go to and youre begging for forgivness in court and a transcriptionist is transcribing onto a page in english directly what you said in english (DNA and RNA same language and same place) 

It goes outside and someone else doesn’t speak englisha dn you have to translate (PROTEINS diff language/ diff place) 

 

A DNA molecule DOES NOT BECOME an RNA molecule they just serve as a template 

DNA is your recipe book you try to make a cake using it but the book does not become a test 

WATCH OUT FOR THIS MAKE SURE YOU READ CAREFULLY YOULL HAVE TONS OF TIME