Intro into AS (transition) Flashcards
Prokaryotes
single celled organisms (bacteria), they have:
- no nucleus with circular DNA free in the cytoplasm
- cell wall made from peptidoglycan
- no membrane bound organelles
- small ribosomes
Eukaryotes (animal cells)
- linear DNA contained inside a nucleus
- no cell wall
- larger ribosomes and many membrane-bound organelles
Eukaryotes (plant cells)
- a cell wall
- a large vacuole containing cell sap
- chloroplasts
facilitated diffusion
- Large molecules cannot diffuse across cell membranes by themselves. They must be helped by carrier proteins.
- Each molecule has its own carrier protein that allows the molecule through the cell membrane without the need for energy
active transport requirements
- a carrier protein
- energy (ATP)
- against a concentration gradient
hydrogen bonds (in DNA)
Each base in a DNA strand links to a base on the opposite strand in the helix to form cross-links of hydrogen bonds
gene
a sequence of DNA which codes for a protein
A (DNA)
Adenine
T (DNA)
Thymine
G (DNA)
Guanine
C (DNA)
Cytosine
The two processes in protein synthesis
- transcription (takes place in the nucleus)
- translation (takes place at the ribosomes)
Protein synthesis process
- A complementary mRNA strand is made using the DNA as a template
- The mRNA leaves the nucleus and attaches to the ribosome in the cytoplasm
- A triplet of bases on the mRNA (codon) code for specific amino acids
- The amino acids are delivered to the ribosome by tRNA
- Peptide bonds are formed between the amino acid to make the polypeptide
Atrioventricular valves (between atrium and ventricles)
- open to allow blood to flow from the atrium into the ventricles
- close when the pressure in the ventricles rises to prevent backflow
Semilunar valves (in the aorta and pumonary artery)
- open to allow blood from the ventricles to flow into the arteries
- close to prevent backflow into the ventricles as the heart relaxes
How is the low oxygen concentration maintained in the blood near the alveolus?
the blood is moving and carrying oxygen away
pulmonary system
pumps blood around the lungs
systemic system
pumps blood around the rest of the body
taxonomy
- science of desribing, classifying and naming living organisms
- aim is to group organisms to accurately identify them and represent their ancestral relationships
why is classification important?
- make sure international biologists are referring to same one when discussing
- to monitor changes in populations of different types of organisms
- to know how different types of living organisms are related to eachother
morphology
the study of the external features (size, shape and structure) and the relationships in the structures of a particular organism or among organisms
anatomy
deals with the study of shape, structure, and internal features of an organism
linnaean system
a system of classifying all organisms into groups according to similarities in their characteristics
more accurate means of classification
the sequence of bases in DNA and of amino acids in proteins
