Cellular biology (term 1) Flashcards
What process occurs in ribosomes?
Biosynthesis
- production of complex molecules in living organism
- controlled by DNA
think of ribosomal RNA (rRNA, tRNA, mRNA)
what are the characteristics of living things?
MRS GREN
* movement
* reproduce
* sense
* grow & develop
* respire
* excrete
* nutrition
* living things control their internal conditions for their cells to be in their optimal physical & chemical environment
* living things are able to evolve
* living things are made of organised structures
What are the 5 unifying themes in biology?
- evolution
- organisation (structure)
- information (DNA)
- interactions
- energy & matter
What are the sizes of various biological structures?
* atoms
* molecules
* ribosomes
* viruses
* bacteria
* animal & plant cells
* (frog egg & egg cell)
- atoms: picometer (10^-12) to nanometer (10^-9)
- molecules: nanometer
- ribosomes: 20nm
- viruses: 10-300nm
- bacteria: 1-10 micrometers
- animal & plant cells: 10-100 micrometer
- (frog egg & egg cell): 2mm & 120 micrometers
What are the different levels of organisation of life?
how is the hierarchy of biological organisation organised?
- biosphere
- ecosystems
- communities
- populations
- organisms/ individuals
- systems
- organs
- tissues
- cells
- organelles
- molecules
- atoms
It’s organised from largest to smallest (reductionism)
Which molecules build up living organisms?
- carbohydrates
- lipids
- proteins
- nucleic acids
- (water)
What chemical roles do carbohydrates have?
Used for:
* energy
* structure (plant cell wall)
* adhesion (the binding of 2 or more cells together)
* signalling (receptor and antigens)
What chemical roles do lipids have?
- energy storage
- structure (cell membranes -> phospholipids)
- signalling (steroid hormones)
- heat insulation
- shock absorption
- buoyancy
What chemical roles do proteins have?
- structure
- building blocks
- signalling
- biological catalysts (enzymes)
- contraction
- defense
- transport
What chemical roles do nucleic acids have?
- storage
- expressions of genetic information (e.g. deoxyribo nucleic acid -> DNA)
What are the properties of water that make it “the molecule of life”?
- water is a polar molecule (its overall charge is unevenly distributed)
- water molecules can form hydrogen bonds
- cohesion of water molecules: this is responsible for water transport in plants and surface tension
- water high specific heat/ ability to moderate temperature: allows a relative steady temperature within water bodies
- ice has a lower density than water/ expansion upon freezing: (it floats) allows life under frozen seas
- versatility as a solvent/ water is the universal solvent: polar substances & ions dissolve in water
What is mitosis used for in cells?
- growth
- repair/healing
- asexual reproduction
- cancerous cell growth/increase (cancer cells have a higher mitotic index than regular cells)
What is the mitotic index?
- a percentage of how many cells are dividing/ performing mitosis
mitotic index = (number of cells in mitosis/ total number of cells) x 100
Mnemonic for mitosis
I - interphase
Party - prophase
More - metaphase
At - anaphase
The - telophase
Club - cytokinesis
Which areas of the body have cells that undergo a lot of mitosis?
Which cell types don’t?
skin and bone tissues have a lot of mitosis
brain cells don’t replicate much and heart muscle doesn’t repair itself much
What different form of electron microscopy are there?
-
transmission EM: you take a cut of the sample/cell
* scan EM: observe the surface of the sample/cell
what are the 4 emergent properties of water that contribute to Earth’s suitability as an environment for life?
- cohesivie behaviour: a
- ability to moderate temperature
- expansion upon freezing
- versatility as a solvent
What is meant by cohesion of water molecules/ cohesive behaviour of water?
What is a result of this property of water?
*
What is meant by thermal energy on the molecular level?
- the kinetic energy associated with the random movement of atoms or molecules is called thermal energy
- thermal energy is related to temperature, but they are 2 different things
What is the specific heat of a substance defined by?
What is the relevance of the high specific heat of water to life on Earth? (what does it affect on earth?)
- It is defined as the amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1°C. (1 calorie per gram per °C)
- milder climate at coastal areas due to the in summer heated up ocean cooling down in winter and releasing heat into the air –> keeps temp. fluctuations within limits that allow life
- the hsh tends to stabilize the ocean temp. creating an ideal environmental for marine life
- individuals are primarily made up of water and can therefore resist changes in their own temp. better
