Anything and Everything y2 Flashcards
1
Q
What are the reaction equations for aerobic respiration, anaerobic respiration in humans, and anaerobic respiration in yeasts?
A
-
Aerobic respiration:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Large amount of energy -
Anaerobic respiration in humans:
C₆H₁₂O₆ → 3C₃H₆O₃ + Small amount of energy -
Anaerobic respiration in yeasts:
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + Small amount of energy
2
Q
Explain, in terms of respiration, what happens in the muscles during and after exercise.
A
- Muscles contract vigorously, causing rate of aerobic respiration and oxygen consumption to increase
- Heart rate and breathing rate increase, enabling more oxygen to reach muscles
- When oxygen intake does not meet oxygen demand, oxygen debt occurs and anaerobic respiration takes over from aerobic respiration
- Lactic acid accumulates, leading to fatigue and muscle pain
- After exercise, lactic acid is oxidised in the liver to produce energy, converting remaining lactic acid back to glucose
3
Q
State the adaptations of the nasal cavity, trachea and bronchi
A
- Nasal cavity:
Hair and mucus layer to trap dust and foreign particles - Trachea:
Supported by C-shaped rings of cartilage to ensure it is always open -
Walls of trachea and bronchi:
Gland cells to secrete mucus layer, trapping dust and bacteria
Ciliated epithelial cells to sweep trapped dust and bacteria into pharynx
4
Q
State the adaptations of the alveoli
A
- Numerous and small in size to increase SA:V ratio
- Well supplied with blood capillaries to maintain constant flow of blood and ensure steep diffusion gradient
- Coated with film of water to allow gases to dissolve and diffuse more efficiently
- One-cell thick wall to minimise diffusion distance
5
Q
State what happens during inspiration
A
- Diaphragm contracts and flattens
- Internal intercostal muscles relax, external intercotal muscles contract
- Rib cage moves upwards and outwards
- Thoracic volume increases
- Pressure in lungs decreases to below surrounding air
- Air is drawn in
6
Q
What are the chemicals found in smoke and their effects?
A
- Nicotine:
Highly addictive
Makes blood clot more easily - Carbon monoxide:
Binds to haemoglobin, decreasing ability of RBCs to transport oxygen
Increases rate of fat deposits on artery walls leading to atherosclerosis - Tar:
Paralyses cilia lining in air passages, leading to less efficient gaseous exchange
7
Q
What is the composition of blood and their adaptations/functions?
A
- 55% Plasma:
Mostly water
Transports proteins, mineral salts, food substances, waste products and hormones - 44% Red blood cells:
No nucleus, biconcave shape to increase SA:V ratio
Elastic to squeeze through blood capillaries
Transports oxygen - 1% White blood cells, platelets:
Lymphocytes produce antibodies that bind to antigens on pathogens, causing clumping
Phagocytes surround and engulf pathogens, destroying them
Platelets begin process of blood clotting when damaged
7
Q
What are the symptoms and effects of chronic bronchitis and emphysema?
A
- Chronic bronchitis:
Infection of the bronchi, inflaming epithelium of airways and causing excessive mucus, leading to breathing difficulties and coughing - Emphysema:
Breakdown of alveolar walls due to excessive coughing, reducing SA:V ratio leading to decreased rate of gaseous exchange
8
Q
Describe the mechanism of blood clotting
A
- Damaged platelets release thrombokinase
- Thrombokinase and Ca²⁺ ions convert inactive prothrombin to thrombin
- Active thrombin converts soluble fibrinogen to insoluble fibrin
9
Q
Describe the 3 ways that carbon dioxide is transported in the blood
A
- 70% diffuses into red blood cells and forms carbonic acid, which is catalysed by carbonic anhydrase. Carbonic acid dissociates to form hydrogen ions and bicarbonate ions, which diffuse back into plasma
- 23% dissolved in plasma directly
- 7% binds to haemoglobin in red blood cells
10
Q
State how blood is transported by the vena cava, pulmonary artery, pulmonary vein and aorta
A
- Vena cava transports deoxygenated blood from rest of body to heart
- Pulmonary artery transports deoxygenated blood from heart to lungs
- Pulmonary vein transports oxygenated blood from lungs to heart
- Aorta transports oxygenated blood from heart to rest of body
Coronary arteries are connected to aorta
11
Q
Describe the location of the 4 valves in the heart
A
- Tricuspid valve/Right atrioventricular valve is located between right atrium and right ventricle
- Bicuspid valve/Left atrioventricular valve is located between left atrium and left ventricle
- Pulmonary valve is located between right ventricle and pulmonary artery
- Aortic valve is located between left ventricle and aorta
Aortic and Pulmonary valves are also referred to as semilunar valves
12
Q
Describe and explain how to determine if two blood groups are compatible for donation
A
If the antigens on the donor’s red blood cells and the antibodies in the recipient’s plasma match, they are incompatible. If they are mixed, the antibodies in the recipient’s plasma will bind to their respective antigens on the donor’s red blood cells, causing agglutination.
13
Q
State the features/adaptations of the 3 main types of blood vessels
A
- Arteries:
High pressure, small lumen relative to diameter
Thick muscular walls to prevent rupture, can contract and relax to cause vasoconstriction/vasodilation
Elastic fibres that can stretch and spring - Veins:
Low pressure, large lumen relative to diameter
Valves to prevent backflow of blood - Blood capillaries:
Largest lumen relative to diameter
One-cell thick epithelium to reduce diffusion distance
Extensive network to increase total cross-sectional area leading to more efficient transport of subtances between cells
14
Q
Describe exactly what happens during the 3 stages of the cardiac cycle
A
- Atrial systole and ventricular diastole (~0.1s):
Atria contracts, forcing blood in atrium to enter ventricles
Pressure in atria increase - Atrial diastole and ventricular systole (~0.3s):
Atria relax and ventricles contract, forcing in ventricles to enter aorta/pulmonary artery
Pressure in ventricles increase, pressure in atria decrease
Blood hits atrioventricular valves and backflow is prevented, causing “lub” sound
Wall of aorta stretches due to influx of blood - Atrial diastole and ventricular diastole (~0.4s):
Ventricles relax
Pressure in ventricles decrease
Blood hits semilunar valves and backflow is prevented, causing “dub” sound
Walls of aorta spring back, causing slight bump in left ventricular pressure (dicrotic notch)
15
Q
Define a gene, allele, genotype and phenotype
A
- Gene:
A section of DNA at a specific location on a chromosome that contains information that defines a trait - Allele:
A specific variant of a gene - Genotype:
The genetic makeup of an organism - Phenotype:
The observable traits of an organism
16
Q
Define codominance and incomplete dominance, discontinuous variation and continuous variation
A
- Codominance:
When the effects of two alleles are mixed in a heterozygous environment - Incomplete dominance:
When the effects of two alleles are equally expressed in a heterozygous environment - Discontinuous variation:
A trait with a few, clear-cut phenotypes that are controlled by one/a few genes, and not affected by the environment - Continuous variation:
A trait with a range of phenotypes that are controlled by many genes with additive effect, and can be affected by the environment
17
Q
Define a calyx, corolla, stamen, androecium, carpel, gynoecium and inflorescence
A
- Corolla: Collective noun for petals
- Calyx: Collective noun for sepals
- Stamen: Anther and filament, male reproductive parts of flower
- Androecium: Collective noun for stamen
- Carpel: Stigma, style and ovary, female reproductive parts of flower
- Gynoecium: Collective noun for carpel
- Inflorescence: Cluster of flowers, common in wind-pollinated plants
18
Q
State the functions of petals, sepals, anther, filament, stigma and style
A
- Petal: Brightly coloured to attract insects, providing a landing platform (insect-pollinated flowers)
- Sepal: Protects flower in bud stage
- Anther: Produces pollen grains
- Filament: Keeps anther upright in a position suitable to disperse pollen grains
- Stigma: Swollen structure, receives pollen grains and secretes sugary fluid to stimulate their germination
- Style: Connects stigma to ovary, holds stigma upright
19
Q
State the differences between self-pollinated and cross-pollinated plants
A
- Self pollinated:
Between same or different flowers on the same plant
Bisexual (both male and female parts)
Anther and stigma mature at same time
Stigma typically situated directly below anthers - Cross pollinated:
Between different plants
Can be dioecious (each flower one gender) or monoecious (each flower two genders)
Anther and stigma mature at different times
Stigma typically situated away from anthers
20
Q
State the difference between insect-pollinated and wind-pollinated flowers
A
- Insect pollinated:
Brightly coloured, large petals
Sweet, fragrant scent
Sticky stigma - Wind pollinated:
Dull coloured, small petals
Long and pendulous anthers
Large, feathery stigma
21
Q
Describe the process of double fertilisation
A
- Pollen grain lands on stigma, which secretes sugary fluid, causing pollen grain to germinate
- Pollen tube nucleus secretes enzymes to digest stigma and style, forming pollen tube
- Pollen tube travels down style into ovary, and enteres ovule through micropyle
- Generative nucleus undergoes mitosis to form 2 haploid male gametes
- One male gamete fuses with haploid ovum to form diploid zygote, other male gamete fuses with 2 haploid polar nuclei to form triploid endosperm
Ensures that plants do not waste energy by forming endosperm for ovules that are not fertilised
22
Q
Describe the effects of puberty on males and females
A
- Male:
Larynx enlarges, voice deepens
Increased growth of pubic hair, facial hair and armpit hair
Penis and testes enlarge and mature, testes start producing sperm
Increased levels of GnRH, testosterone - Female:
Breasts and uterus enlarge
Increased growth of pubic hair
Sex organs mature, beginning of ovarian cycle and menstruation
Increased levels of GnRH, oestrogen, progesterone
23
Q
Describe the functions of the parts of the male reproductive system
A
- Testes: Produces sperm and secretes testosterone and other sex hormones
- Scrotum: Sac of skin that supports the testes, maintaining optimal temperature of 33-34°C for sperm growth
- Epididymis: Coiled duct next to each testis, storing inactive sperm
- Sperm duct : Conducts sperm from testes or epididymis to penis
- Seminal vesicle: Temporarily stores sperm before it is released into urethra
- Cowper’s gland and Prostate gland: Releases fluids containing nutrients and enzymes that activate sperm
24
Describe the **functions** of the **parts** of the **female** reproductive system
* Ovary: Stores **diploid** **primary** follicles and produces **ovum**, secreted **oestrogen** and **progesterone**
* Fimbria: **Ciliated** structure between **ovaries** and **fallopian** tube that **sweep** ovum into fallopian tube
* Fallopian tube: Conducts **ovum** from **ovary** to **uterus**, acts as site of **fertilisation**
* Endometrium: Outer **muscular layer** of **uterus**, acts as site of **implantation** of embryo
25
Describe the phases of the **ovarian cycle**
* Follicular phase:
**GnRH** stimulates secretion of **FSH**, stimulating **development** of **primary** follicle into **Graafian** follicle
Mature **haploid ovum** develops in Graafian follicle
**Graafian** follicle secretes **oestrogen**, repairing **endometrium** and stimulating release of **LH**
* Ovulation phase:
Spike in **LH** causes rupture of **Graafian** follicle, releasing **ovum** into fallopian tube and producing **corpus luteum**
Start of **fertile period**
* Luteal phase:
Corpus luteum secretes **oestrogen** and **progesterone**, **thickening** endometrium to allow **implantation** of embryo
**Oestrogen** and **progesterone** have **negative feedback** on **pituitary gland**, decreasing secretion of **FSH** and **LH**
If fertilisation **unsuccessful**, corpus luteum **breaks down**, **decreasing** secretion of oestrogen and progesterone
26
Describe the phases of the **menstrual cycle**
* Menstrual phase (Day 1-5):
**Decrease** in levels of **oestrogen** and **progesterone** leads to **shedding** of endometrium, degenerated ovum and blood, which are **removed** through the vagina
**Rise** in **GnRH** stimulates secretion of **FSH**, stimulating start of **ovarian cycle**
* Proliferative phase (Day 6-13):
**High** levels of **FSH** stimulate secretion of **oestrogen**, stimulating **repair and growth** of endometrium
**High** levels of **oestrogen** stimulate secretion of **GnRH**, which stimulates secretion of **LH**
* Ovulation (Day 14):
**Spike** in **LH** stimulates **rupture** of **Graafian follicle** and release of **ovum** into fallopian tube
Ovum remains **viable** for 1-3 days (**fertile period**)
* Secretory phase (Day 15-28):
High levels of **oestrogen** and **progesterone** thicken and maintain thickness of **endometrium**, and have **negative feedback** on **GnRH**, **surpressing** secretion of **FSH and LH**
Preparation of **implantation** of **embryo** in endometrium
If fertilisation does **not** occur, corpus luteum **degenerates**, causing **drop** in levels of **oestrogen** and **progesterone**
27
State the **functions/adaptations** of the **placenta** and **amniotic sac**
* Placenta:
**Maternal blood** bathes **whole** surface of **chorionic villi** to increase **SA:V ratio**
Chorionic villi have **highly folded** structure to increase **SA:V ratio**
**Continuous** flow of **maternal** blood in maternal **blood pools** and **foetal** blood in foetal **blood capillaries** to maintain steep **diffusion gradient**
* Amniotic sac:
Contains amniotic **fluid**, which **supports** and **cushions** foetus to prevent bodily **injury**
Maintains foetal **body temperature**
**Lubricates** vagina during birth
28
State the **corrective mechanisms** of the body when there is **high** external temperature.
* Arterioles vasodilate, shunt vessels vasoconstrict to increase flow of blood to capillaries at skin surface
* Sweat glands increase sweat production to increase heat lost as latent heat of vaporatisation during evaporation
* Hair erector muscles relax to allow hair to lie flat
* Rate of metabolic activities and respiration decreases to decrease heat produced
