Biology 101 Flashcards
State the two main reasons why food is required by all living organisms.
Energy
Growth
What is the ratio of hydrogen atoms to oxygen atoms in a carbohydrate?
2:1
Give a structural role of lipids in cells.
It is a component of cell membranes.
Give a metabolic role of lipids in cells.
As a source of energy
Give an example of a fat‐soluble vitamin.
Vitamin D
Vitamin E
Vitamin K
Vitamin A
Name a disorder due to a dietary deficiency of the vitamins ; A, D, E and K.
Vitamin D - Osteomalacia or Osteoporosis
Vitamin E - Anaemia
Vitamin K - Easy Bruising
Vitamin A - Night Blindness
What is meant by the term hypothesis?
This is an educated guess based on observations
Explain what is meant by double‐blind testing.
This is a form of testing whereby neither the tester nor the subject knows who gets the drug (or who gets the placebo)
Explain the necessity for random selection.
for a fair test and for unbiased results
Give two other features of good experimental design.
A control/ only one variable/ safe (procedure)/ large sample size/ repeatable/ replicates
Where are the results of scientific research usually first published?
Scientific Journal
Why is it important that scientists publish the results of their research?
So that others can learn (from their work)
So others can repeat it
Information made widely available
What is meant by the term tissue?
A group of cells working together to carry out a similar function.
Name two types of animal tissue.
Epithelial (or epidermis)/ muscle/ connective/ nervous/ adipose/ blood/ bone/ cartilage/ tendon/
ligament
What is meant by the term tissue culture?
Growth of cells in vitro
Give one other application of tissue culture.
Plant breeding/ micro-propagation/ plant propagation/ vegetative propagation/ skin grafts/ cancer research/ IVF/ vaccine production/ antibody production/ replacement organs
Which type of microscope is used in the school laboratory to observe cells?
Light Microscope
Give two observable events that happen during prophase.
Nuclear membrane disappears
Chromosomes are visible
After mitosis, what happens in animal cells?
A cleavage is formed
After mitosis, what happens in plant cells?
A cell plate is formed
What word is used to describe the shape of the two faces of the red blood cells?
Biconcave
What feature of red blood cells allows them to pass through the narrow capillaries?
They are flexible
Name the molecule in red blood cells that carries oxygen.
Haemoglobin
Human red blood cells live for about 120 days.
Give a reason for this, based on the composition of these cells.
No nucleus or no mitochondria or no organelles or cannot reproduce
Give a location in the body where red blood cells are produced
Bone Marrow
Give a location in the body where red blood cells are usually broken down.
Liver or Spleen
Name the transport fluid in humans that does not contain red blood cells.
Lymph
Name the blood vessel from which the capillary arises.
Pulmonary artery (arteriole)
Give any three features of alveoli or their capillaries that allow for efficient gas exchange.
The alveoli’s membrane (or wall) is thin / it has a Large surface area/ Large numbers/ Moist surface/
Name a disorder of the human breathing system and suggest how it is caused and treated.
Asthma
caused by dust or allergens
treated using an inhaler.
What is the use of a Biuret Reagent
to test for protein
What is the use of Benedict’s solution
to test for reducing sugar
When preparing a sample of cheek cells on a microscope slide, why did you place a coverslip over the cells?
To prevent (the cells) from drying out or to protect the (objective) lens (from water or from stain) or to hold sample in place or easier to see
When preparing a sample of cheek cells on a microscope slide, why did you apply methylene blue to the cells?
To stain (the cells) or to make (the cells) easier to see
When extracting DNA from plant tissue, why did you use washing up liquid?
To breakdown the cell membrane
When extracting DNA from plant tissue, why did you use freezer‐cold ethanol?
To precipitate (the DNA) or to make (the DNA) insoluble or take (the DNA) out of solution or to make (the DNA) visible
When using seeds to investigate the effect of IAA on plant tissue, why did you carry out a serial dilution of an IAA solution?
(To make solutions of) different concentrations (of IAA)
When using seeds to investigate the effect of IAA on plant tissue, why did you place the seeds on a grid in Petri dishes?
To measure the growth (of root or shoot accurately)
When carrying out an activity to investigate osmosis why did you use Visking tubing?
To act as a selectively permeable membrane or to mimic the plasma membrane
When carrying out an activity to investigate osmosis how did you know osmosis had taken place?
Mass of tubing increased (or decreased) or tubing got fuller (or less full) or increased turgidity
Is oxygen necessary for fermentation?
No
Where in the cell does fermentation take place?
Cytosol or Cytoplasm
To prepare alcohol using yeast, from which substance did the yeast make the alcohol.
Glucose or sugar
What is the optimum temperature for the fermentation process?
How was this temperature maintained throughout the fermentation?
Any temperature or range within 20 °C – 35 °C
The temperature was maintained using a water bath or incubator.
How did you know when the fermentation was finished?
No more gas (carbon dioxide) produced / no more bubbles
How did you test for the presence of alcohol?
Give the colour of the positive result of the test.
Iodoform test or (potassium) iodide and (sodium) hypochlorite.
Positive colour: Yellow
What is meant by the term dicotyledonous?
It means it has two seed leaves
Answer the following questions in relation to your preparation and microscopic examination of a transverse section of a dicotyledonous stem;
i) Name the plant you used.
ii) Why is it important to use a very thin section when examining the tissues in the stem?
iii) Describe two steps you took to cut the stem safely.
iv) How did you transfer the section to the microscope slide?
v) Name the part of the microscope you used to bring the section into a sharp focus.
i) Buttercup or sunflower or rose or ivy or busy lizzy or geranium.
ii) To allow light to pass through (effectively or well) or to see (the cells) clearly.
iii) A knife/ blade/ scalpel was used
it was cut away from the body
iv) using forceps or a tweezer
v) the fine focus wheel
What is the importance in nature of recycling elements such as carbon and nitrogen?
To return (elements) to environment or so that (elements) can be reused (by organisms)
Name two of the types of bacteria that play a role in the nitrogen cycle.
Nitrogen fixing/ nitrifying/ denitrifying/ decomposers or saprophytes
Explain what is meant by predation
Catching (or hunting) and killing and eating another organism
Explain what is meant by the conservation of species
Management of the environment (or of ecosystem or of habitat) or management of species (or of plants and animals) or maintenance of biodiversity or protect a species or prevention of extinction
From your knowledge of ecological surveys, explain the meaning of the terms:
- Quantitative
- Qualitative.
- Quantitative - Number of (or amount of or measurement of) organisms (or species or plants or animals present) or measurement of an abiotic factor.
- Qualitative - Presence of (or absence) an organism (or species or plant or animal).
In the course of your ecological studies you investigated an ecosystem.
Name this ecosystem and describe how you conducted a quantitative survey of flora present in it.
how did you present the results of your survey?
Suggest a possible source of error in your survey.
Survey was conducted using a quadrat. This was placed over a random area in the habitat and the number of flora present was counted and recorded. This was repeated a number of times.
Using a table or chart or graph
Not random or sample too small or plant misidentified or miscounting or Miscalculating
Name the sugar present in DNA.
Deoxyribose
Other than the sugar, give two structural differences between DNA and RNA.
DNA is double-stranded or RNA is single-stranded
DNA has Thymine or RNA has Uracil
Protein synthesis is a complex process, involving both transcription and translation, that occurs in all cells.
(i) Where does transcription occur in animal and plant cells?
(ii) Where precisely in the cell does translation occur?
(iii) Name the three types of RNA involved in protein synthesis.
i) Nucleus
ii) Ribosome
iii) Messenger RNA (or mRNA)
Ribosomal RNA (or rRNA)
Transfer RNA (or tRNA)
Describe the events that occur during translation, leading to the formation of a functional protein
mRNA goes to a ribosome, tRNA are attracted to the mRNA because their anticodons are attracted to the codons on the mRNA. tRNA attaches to mRNA and brings a particular amino acid to the ribosome. a sequence of amino acids is formed until a stop codon is reached. The mRNA sequence is now complete and a new protein is produced.
what is a sex linkage?
A gene (or genes) present on the X (or Y, or sex) chromosome
what does the term, ‘heterozygous’ mean?
When two alleles (for a trait) are different
what is meant by a genotype?
The genetic make-up or the genes present
What is meant by the term metabolism?
(All) the chemical reactions in an organism (or in cells or in the body)
Give an example of one anabolic reaction and one catabolic reaction in animals.
Anabolic reaction in animals:
Protein synthesis or DNA replication (synthesis)
Catabolic reaction in animals:
Respiration or digestion
(i) What is an enzyme?
(ii) Which type of biomolecule are enzymes?
(iii) Name two factors that affect enzyme action.
(iv) What is meant by the term specificity in relation to enzyme activity.
(v) Name the part of an enzyme responsible for its specificity.
i) Biological catalyst or protein catalyst.
ii) Protein.
iii) Temperature and pH
iv) (An enzyme) can act on only one (or on a particular or a certain) substrate (group) (or molecule)
v) The active site.
Give a detailed account of how enzymes work.
Active site changes shape to allow a perfect fit. When the substrate fits the enzyme perfectly at the active site, an enzyme-substrate complex is made. Then the products are formed and released. The enzyme returns to its original shape and can be reused
Where does photosynthesis occur?
In the chloroplast
Give a balanced chemical equation to summarise the process of photosynthesis.
6CO2 + 6H2O → C6H12O6 + 6O2
Name two products of the light‐dependent stage of photosynthesis.
ATP/ NADPH or protons (or H+ or H ions) or electrons)/ oxygen
Outline the events of the light‐independent stage in photosynthesis
NADPH releases H+ and 2 electrons. CO2 combines with the H+ and 2 electrons. Energy from ATP is used to produce glucose.
Contraception can include natural, mechanical, and chemical methods.
Give one example of each of the above types of contraception.
Natural: Withdrawal or abstinence
Mechanical: Condom or diaphragm or coil (or IUD) or vasectomy or tube ligation
Chemical: Pill or hormonal or vaginal ring or spermicide or implant
where is the site of meiosis in the female reproductive system?
ovary
where is the site of fertilisation in the female reproductive system?
Oviduct (Fallopian tube)
Name a human female menstrual disorder. For this disorder give:
- A possible cause
- A method of treatment.
Disorder: endometriosis
Cause: Menstrual blood flowing into oviduct
Treatment: Surgery
What is meant by the term implantation?
Embedding (or attaching) (of the fertilised egg) (in)to the endometrium (or lining of uterus).
Outline what happens to each of the following after implantation has taken place:
- The level of the hormone progesterone in the blood
- The endometrium.
- the progesterone level increases
2. the endometrium thickens
Name, in the correct order, the developmental stages from the fertilised egg to implantation.
- Morula
2. Blastocyst
Embryo cells organise into three germ layers. Name each of these layers.
Ectoderm Mesoderm Endoderm
Give a function of the medulla oblongata
Controls (or regulates) involuntary actions or controls (or regulates) breathing (or heart function or digestion or sneezing or coughing or swallowing or blood pressure or vomiting)
Give a function of the cerebellum
Controls (or regulates) voluntary movements.
Controls (or regulates) posture (or balance or walking or writing or fine muscle movements or speech) or coordination
The brain is composed of both grey matter and white matter.
- Why is grey matter so called?
- Why is white matter so called?
- Grey matter: Composed of cell bodies
2. White matter: Composed of myelin or composed of axons
What is meant by the term endocrine?
These are ductless glands. They secrete directly into the blood.
Name a hormone secreted by the pituitary gland.
Give a function of this hormone in the human body.
Oxytocin
Causes contractions of the uterine muscle resulting in the onset of labour
Name one gland in the human body that has both endocrine and exocrine function.
Pancreas or testis or ovary or liver or kidney
Explain vaccination
This is a non-harmful dose of the pathogen introduced (or injected) into an organism (or into the body) to Stimulates (active) immunity by producing antibodies. This prevents infectious disease or prevents spread of disease.
Explain antibiotic resistance in bacteria.
Antibiotic resistant bacteria are not affected by antibiotics This can be caused by overuse or misuse of antibiotics or by failure to complete a course of antibiotics. Due to this, the bacteria mutate or evolve over time and acquire increased resistance.
Explain the mechanism of phototropism in plants.
Auxin produced in shoot tip (or meristem). Plant shoot exposed to (more) light on one side. Auxin diffuses (moves) down the shaded (dark) side of the shoot.More elongation (or growth) of the shaded side (cells). Shoot grows (or bends) towards the light
Explain batch food processing.
This is carried out in a bioreactor. Certain amount of micro-organisms (or bacteria or fungi) (or food or nutrients or substrate) is added at the start of the process. Micro-organisms (or bacteria or fungi) go through lag, log and stationary stages. Product is removed (at the end of the process)
Explain the cause of the sounds created during the cardiac cycle.
The sounds are ‘lub’ + ‘dub’. They are caused by valves closing. Tricuspid and bicuspid (or sinoatrial valves) close to cause the ‘lub’ sound. Semilunar valves close to cause the ‘dub’ sound.
Give two functions of the skeleton.
Movement / protection (of internal organs) / support (or shape) / production of blood cells
Name the two main parts of the appendicular skeleton, to which the limbs are attached.
Pectoral girdle (or shoulders) and the pelvis (or pelvic girdle or hips)
Name two of the types of bones that make up the foot.
Tarsals/ metatarsals/ phalanges (or digits)
What is meant by the term antagonistic muscle pair?
(Two) muscles that work with opposing actions or (two) muscles that have opposite effects or when one contracts the other relaxes
Name an antagonistic muscle pair in the human body.
Describe in full how this antagonistic muscle pair works.
The biceps and triceps
Biceps contract to flex or raise or bend the arm
Triceps contract to extend or lower or straighten the arm
What mode of nutrition does Rhizopus use?
Saprophytic or heterotrophic
Describe an environmental condition that would cause Rhizopus to reproduce
sexually.
Lack of water or unsuitable (or adverse or extreme) temperature or unsuitable (or adverse or extreme) pH or lack of nutrients
Describe in detail the process of sexual reproduction in Rhizopus.
Opposite ( or + and - ) strains of hypha are present. Swellings form and progametangia is produced. Fusion of nuclei (or fertilisation or zygote formation) occurs and the zygospore is formed. Germination of zygospore by meiosis
What is meant by the term digestion?
Breaking down food.
Give two reasons why digestion is necessary.
To make food soluble/ easier to absorb/ easier to transport
Name and describe the method by which food is passed along the alimentary canal.
Peristalsis.
These are muscular contractions of the walls of the alimentary canal.
Name an enzyme that digests dietary protein.
Where is this enzyme produced?
Where is this enzyme active?
Name the products formed by the complete digestion of a protein molecule.
Protease or pepsin (or other named protease)
Stomach or small intestine or duodenum or ileum or pancreas.
Stomach or small intestine or duodenum or ileum
Amino acids
Name the blood vessel that transports protein digestion products to the liver.
Hepatic portal vein
Describe in detail the development of the embryo sac from a megaspore mother‐cell.
Diploid megaspore mother-cell divides by meiosis giving four haploid (daughter) cells. Only one survives. This becomes the embryo sac. The embryo sac nucleus divides by mitosis three times to give eight haploid nuclei. Two (of the haploid nuclei) become the polar nuclei while one (haploid nucleus) becomes the egg (nucleus).
A double fertilisation occurs in the embryo sac.
- Outline what happens during each fertilisation.
- State what is produced by each fertilisation.
- One (male) gamete (or sperm nucleus) fuses (or joins or combines) with the egg.
One (male) gamete (or sperm nucleus) fuses (or joins or combines) with the (two) polar nuclei. - A (diploid) zygote.
A triploid nucleus or a triploid endosperm.
