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Biology S4 Revision 2017 > Revision 2018 > Flashcards

Flashcards in Revision 2018 Deck (84):

What is a double helix?

A double helix is the shape of the DNA molecule, with two strands twisted together in a spiral.


What is mRNA?

mRNA is genetic information that passes out of the nucleus into the cytoplasm.


What are amino acids?

Amino acids are the small molecules that join together in long chains to make proteins. There are 20 different ones.


What is meiosis?

Meiosis is cell division that produces the genes.


What is mitosis?

Mitosis is cell division that produces two cells, for growth + repair.


What is the triplet code?

(3 bases) The triplet code is the information needed to make one amino acid.


What do ribosomes do?

Ribosomes are the place where protein synthesis takes place.


Explain phototropism?

Phototropism is the bending of the plant shoot towards the light.


What are chromosomes?

Chromosomes are long thin, thread- like structures in the nucleus of a cell made from a molecule of DNA. (46 in humans).


Explain One- gene- one protein theory?

One- gene- one protein theory is the idea that each gene on a chromosome controls the production of one protein in the cell.


Explain Genetic switches?

Genetic switches are where genes in the nucleus turn off and are inactive when a cell becomes specialised.


What is an Specialised cell?

A Specialised cell is one that is adapted for a particular type of job.


Explain Tissues?

Tissues are a group of specialised cells of the same type working together to do a particular job.


What are organs?

Organs are parts of plants or animals made up of different tissues.


Explain what "unspecialised" means.

"Unspecialised" means undifferentiated cells, Stem cells are an example.


What are auxins?

Auxins are plant hormones that affects how plant cells develop.


Explain what meristems are?

Meristems are plant cells that are unspecialised and re- grow whole parts of a plant.


What are bases?

The four bases are: A, T, C and G. They are part of DNA.


Explain what proteins are.

A protein is made from one or more polypeptide chains and each polypeptide chain is built from smaller molecules called ‘amino acids’.

Proteins also play a role in movement, structural support, storage, communication between cells, digestion and the transport of substances around the body.


What is the photosynthesis word equation?

The photosynthesis word equation is:

Carbon dioxide + water → Glucose + Oxygen.


What is the symbol equation for this process?

The symbol equation for this process is:

6CO2 + 6H2O → C₆H120₆ + 6O2.


What does a heat shield do?

A heat shield stops heat transferring to the plant.


What does eukaryotic mean?

Eukaryotic is "genetic information that is inside the nucleus of a cell".


Explain Prokaryotic?

Prokaryotic means "that it's a cellular organelle that has no internal membrane".


How do you calculate an RF value?

You would calculate an RF value by this particular formula:

RF= Distance moved by the compound ➗ distance moved by the solvent.


Name 4 uses of glucose in a plant?

Plants use glucose to make:

1). Starch, fats or oils for storage.

2.) Proteins eg. enzymes, chlorophyll.

3). To make cellulose for it's cell walls.

4). To make amino acids for protein synthesis.


What is the word equation for aerobic respiration?

The word equation for aerobic respiration is:

Glucose + Oxygen → Carbon Dioxide + Water + Energy.


What is the word equation for this process?

The word equation for this process is:

C₆H12O₆ + O2 → CO2 + H20.


Define metabolism?

Metabolism is all of the chemical reactions that occur within cells.


Explain Genomes.

Genomes is all of the DNA of an organism.


What does asexual mean?

Asexual means one parent.


Define sexual?

Sexual involves two parents ( gametes).


What does phenotype mean?

Phenotype is the physical characteristics shown.


Define genotype?

Genotype means the alleles a person has.


What does heterozygous mean?

Heterozygous- Has 2 different alleles for a different feature.


Define homozygous?

Homozygous- Has 2 alleles the same for a similar feature.


What are mutations?

Mutations are random changes in the genetic code.


Name the 6 different mutations in chromosomes?

The 6 different mutations in chromosomes are:

1). Inversion.

2). Deletion.

3). Duplication

4). Substitution

5). Insertion

6). Translocation.


Why can mutations be good in a population?

Mutations be good in a population because:

- More variety ( larger gene pod).

- Different colours in hair, birds, eyes. (can give camouflage).

- new beneficial features develop and they can give survival advantage.


Explain why mutations can be bad?

Mutations can be bad because:

- It can cause cancer.

- It could develop features which reduce survival features eg. albino have reduced camouflage.


What is cystic fibrosis?

Cystic fibrosis is the build- up of thick, sticky mucus in the respiratory system, digestive system and the reproductive system.


What are the symptoms of cystic fibrosis?

The symptoms are:

- Prone to infections.

- The mucus in the pancreas affect's the digestion of food.

- There's thick sticky mucus on your lungs - blocked air passages.


What is the treatment for this disorder?

Here's the treatments:

- No cure.

- Physiotherapy

- Inhaled antibiotics.

- Steroids (drugs).

- Airway clearance devices.

- Breathing techniques.


What is the treatments for polydactyl?

Here's the treatments:

- Non- life threatening.

- Surgery.


What does natural selection mean?

Natural selection " is the process in which better suited organisms in a species are selected by nature to pass on their beneficial genes.


Define evolution?

Evolution " is the change in inheritable characterises over time in a species.


What does a gamete mean?

A gamete means Sex cells (Haploid/ Half the genetic information).


Define chromosomes?

Chromosomes are made up of DNA- 46 in the normal body cells,


Explain what gene means?

Gene means a section of chromosome responsible for one characteristic.


What does an allele mean?

Allele means a different version of a gene.


Explain what a Carrier means?

A carrier is someone who has an unexpressed recessive allele due to the presence of a dominant allele.


Define dominant?

Dominant means an allele that always expresses itself ; only one required.


What does recessive mean?

Recessive means an allele that doesn't express itself in the presence of a dominant allele.


Define genetic engineering?

Genetic Engineering is the science of changing the gene sequence in organisms.


Explain gene therapy.

Gene therapy means inserting copies of a normal allele into a chromosome.


Who was Alfred Wallace?

Alfred Wallace jointly identified evolution, natural selection and he identified warning coloration in an organism.


Who was Charles Darwin?

Charles Darwin came up with the theory of evolution by natural selection and he wrote the book 'Origin of species'.


Who was Jean Paul Lamarck?

Jean Paul Lamarck believed environmental features could be passed on. He also came up with 'use it or lose it' theory.


Who was Carl Linnaeus?

Carl Linnaeus classified organisms by their appearance.


Who was Carl Woese?

Carl Woese used RNA to classify organisms.


Define genetic modification?

Genetic modification means taking the gene sequence from one species and inserting it into another species.


What does accuracy mean?

Accuracy means that if a measurement is considered accurate it is to be judged to be close to a true value.


Define precision.

Precision means precise measurements are ones in which there is very little spread about the mean value. Precision depends on only on the extent of random errors- it gives no indication of how close results are to the true value.


What does repeatable mean?

Repeatable means that if a measurement is repeatable the original experimenter repeats the investigation by using the same method and equipment and obtains the same results. Previously known as reliable.


Define reproducible.

Reproducible means that if a measurement is reproducible the investigation will be repeated by person, or by using different equipment or techniques, and the same results are obtained. Previously known as reliable.


What does calibration mean?

Calibration means marking a scale on a measuring instrument or checking readings to see whether it reads zero, in order to check if it has been calibrated correctly.


Define qualitative data.

Qualitative data means that it's non- numerical data such as colour change using universal indicator or colour changes during food tests.


What does quantitive data mean?

Quantitive data means that it's numerical data such as ph 7.4 or a colour change during a continuous testing after every minute.


Define resolution.

Resolution means that it's the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.


What does dependent mean?

Dependent means that it's the variable of which the value is measured for each and every change in the independent variable.


Define independent.

Independent means that it's the variable for which values are changed or selected by the investigator.


Define stem cells.

A stem cell is an undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type, and from which certain other cells arise from differentiation.


What is diffusion?

Diffusion is the random movement of particles form an area of high concentration to a low area of concentration.


Define osmosis.

Osmosis is the passive diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.


Define active transport.

Active transport is the process by which dissolved molecules move across a cell membrane from a lower to a higher concentration.

In active transport, particles move against the concentration gradient- and therefore require an input of energy from the cell.


Define fungi.

Fungi are eukaryotic single- celled organisms that live by decomposing organic material.

Examples : mold, mildews & yeasts


Explain bacteria.

Bacteria are single celled- organisms, sphere, spiral, or rod shaped. No nucleus. Used in fermentation. Examples include E.Coli & Salmonella.


Define virus.

A virus is the smallest of the microbes, strand of DNA, protein coat instead of cell wall. Examples include: Chicken Pox and influenza.


Describe pathogens.

Pathogens are diseases causing microorganism (fungi- athletes foot, bacteria- food poisoning, virus- flu)


Define white blood cells.

White blood cells produce antibodies and antitoxins, engulfs and digests microorganisms, Memory wbc remember previous pathogens and quickly start an immune response.


Explain Vaccines.

Vaccines are dead, weak or part of a disease, initiates an immune response before you get the real disease.


Define Antibiotics.

Antibiotics kill bacteria, BUT NOT VIRUSES.


Explain MMR

MMR is a vaccine against mumps, measles and rubella.


Define antigen.

An antigen is the outside protein coat of a microbe.