Bio Cells And Genetics Flashcards
Nucleus
Contains genetic information stored in chromatin threads, controls all cell activities
Cell membrane
Partially permeable, controls movement/diffusion of substances in and out of the cell
Cytoplasm
Solvent made of water/proteins that contain organelles, made up of phospholipid bi layer
Vacuoles
Store minerals and starch, covered by tonoplast
Ribosomes
Site of protein synthesis / synthesises proteins
Mitochondria
Site of aerobic respiration, releases energy
Golgi apparatus
Modifies and packages proteins for secretion our of cell
Smooth ER
Synthesises lipids and steroids
Rough er
Production and folding of proteins
Different aspects between animal and plant 4
Cell wall
Chloroplasts
Centrioles
Vacuole
Adaptation of root hair cell
Long and narrow protrusion : SA:vol, absorption of minerals and water
Numerous mitochondria
Adaptations of RBC
No nucleus= more haemoglobin
Circular biconcave shape ^SA:vol
Elastic to squeeze thru capillaries
Sickle cell anemia
v SA:vol , v diffusion of O2 into rbcs , v aerobic resp , v energy release = patients tired
Movement of substances format
Particles move from region of higher conc to lower conc down a conc gradient.
(Opp for active transport)
(Water potential for osmosis)
Concentration gradient
Steeper = higher rate of diffusion
Diffusion
Net movement of particles from a region of higher conc to lower conc down a conc gradient.
Osmosis
Net movement of water MOLECULES from region of high WP to low WP down a conc gradient; thru ppm
Active transport
Particles move from low conc to high conc against conc gradient; thru ppm using energy (from aerobic resp)
Higher water potential on cells
Plant : turgid (doesn’t burst cause cell wall)
Animal : bursts, lyses. RBC= haemolysis
Lower water potential on cells
Plant: plasmolysed (membrane and cytoplasm shrinks, becomes flaccid)
Animal cell: crenated
Best solution for plant and animal cells water potential
Plant: higher wp (hypotonic), turgid, remain upright
Animal: the same
Importance of maintaining turgidity in plants
- maintains shape of soft tissues
- keeps plants firm and upright
- loss of turgidity: wilting
Vesicles
Contain substances from er. Pinch off er and fuse with Golgi apparatus.
Secretory vesicles containing the modified substances from GA pinch off and fuse with cell membrane, release contents to cell exterior
DNA Deoxyribose nucleic acid
Each DNA molecule consists of 2 anti-parallel strands (2 strands run in opposite directions) twisted to form a double helix and they each wrap around proteins (histones) to form a single chromatin thread.
nucleotide structure in DNA
DNA is made up of polynucleotides, each nucleotide consisting of a deoxyribose sugar molecule, a phosphate group and a nitrogen containing base.(ATGC)
Function of DNA
carry genetic information and genetic code in genes that is used to synthesize specific polypeptides
DNA complementary bases
Adenine-Thymine/Uracil(RNA), Guanine-Cytosine (Complementary bases)
Genes
Genes are segments of DNA that each code for the synthesis of a single polypeptide.
3 nucleotides in a gene form a codon that codes for the synthesis of one amino acid.
change in nucleotide sequence (gene mutation)
change in the protein product,
eg
albinism (defect in enzyme synthesising melanin) and sickle-cell anaemia ( different from normal cells by one amino acid = sickle)
DNA vs RNA
Responsible for storing and transferring genetic information // Codes for amino acids and acts as a messenger between DNA and ribosomes to synthesise proteins
Deoxyribose sugar molecule // Ribose sugar molecule
Double-stranded // Single-stranded
Ratios of A:T, C:G = 1:1 // No fixed ratio as its single stranded
Adenine - Thymine // Adenine - Uracil
transcription (DNA)
gene unzips and the template strand codes for the transcription of the mRNA (messenger RNA) which is complementary to the template strand and then attaches to the ribosomes found in Rough Endoplasmic Reticulums.
mRNA leaves the nuclear envelope of the nucleus via the nuclear pores to reach the ribosomes
translation (DNA)
starts by mRNA attaching to ribosome) into polypeptides (in the ribosomes) = involves transfer of RNA molecules (tRNA) that are complementary to a codon in the mRNA molecule, with the amino acid attached to it.
When the stop codon is attached, the ribosome leaves the mRNA and polypeptide is produced.
Manufacture of insulin via genetic engineering
- Isolate the human insulin gene via the use of a restriction enzyme to cut the specific gene from the DNA
- Use the same restriction enzyme on the vector molecule such as bacterial plasmid so that they both have complementary sticky ends and can be inserted by DNA ligase into the plasmid
- The recombinant plasmid is inserted into the plasmid to become a transgenic bacterium, via electric shock therapy with the aid of calcium ions
- This is then cultivated in a fermenter and burst open to collect the produced human insulin.
why is heat shock and calcium ions needed in the process of manufacturing insulin
to open the pores of the cell surface membrane of the bacteria for plasmid to leave/enter.
Advantages of Genetic engineering (GE)
- Affordable drugs/medicine like human insulin
- Production of crops that grow in extreme conditions to benefit farmers
- Pesticide resistant crops
- Improved nutritional quality of food
Disadvantages of GE
- Social = lead to class distinctions and religious disputes
- Economic = prices of genetically modified seeds are high = less affordable
- Health = genes for antibiotic resistance may cause human diseases
- Environmental = GE crops may produce toxins that are harmful to insects