exam cram t2 Flashcards
1
Q
what is the cell
A
the fundamental structural and functional unit of all living brings, it is the smallest part of an organisms body which is capable of independent existence and of performing the essential functions of life
2
Q
what do most organisms start off as
A
a zygote
3
Q
what is meant by protoplasm
A
it is the total living substance of a cell, that is, the cytoplasm and the nuclrus
4
Q
what does protoplasm look like
A
translucent somewhat colorless, greyish, brownish fluid
5
Q
what are the common elements in protoplasm
A
carbon, hydrogen, oxygen, nitrogen, sulphur, iron, phosophorus
6
Q
list 4 differences between prokaryotic and eukaryotic cells with 2 examples each
A
- prokaryotik cell: nucleus is not well defined (nucleoid)
eukaryotic: well defined nucleus with a nuclear membrance - prokaryotik: a single length of deoxyribonucleic acid only.
eukaryotic: several lengths of chromosomes containing dna - prokaryotic: small ribosomes
eukaryotic: larger ribosomes - prokaryotic: no other cell organelles
eukaryotic: several organelles like mitochondria, endoplasmic reticulum etc. - eg prokaryotic: bacteria, blue green algae
eg eukaryotic: euglena, amoeba
7
Q
state the 4 structural differences between plant and animal cells
A
- Plant cells have a definite cell wall made up of cellulose while animal cells dont have a cell wall
- plant cells dont have centrosome, animals cells have centrosome
- plant cells have prominent vacuoles, one or more concerned with excretion or secretion, animal cells might not have vacuoles, if any they are small and temporary
- plant cells usually have plastids while animal cells dont have plastids
8
Q
state the three major points of cell theory
A
- the cell is the smallest unit of structure of all living things
- the cell is the unit of function of all living things
- all cells arise from pre-existing cells
9
Q
list 3 functions of the cell wall
A
- gives rigidity and shape to the plant cell
- allows substances in solution to enter and leave the cell
- provides protection.
10
Q
list 3 functions of the plasma membrance
A
- separates content of cell from its surroundings
- regulates the entry of certain solutes and ions
- Maintains shape of animal cell
11
Q
list 3 functions of cytoplasm
A
- different organelles in it have different functions
- all metabolic activities occur here
- medium for initial steps of respiration (production of pyruvic acid) (anaerobic respiration)
12
Q
list 2 functions of endoplasmic reticulum
A
- supportive framework for the cell
- synthesis and transport of proteins and fat
13
Q
list 2 functions of mitochondria
A
- release of energy from pyruvic acid stores in cytoplasm in the form of ATP. Seat of cellular aerobic respiration and stores energy
- synthesis of respiratory enzyme
14
Q
list 2 functions of golgi apparatus
A
- synthesis and secretion of enzymes, hormones etc.
2. formation of acrosome of sperm (only in animals and humans)
15
Q
what is the function of ribosomes
A
protein synthesis
16
Q
list 4 functions of lysosomes
A
- intracellular digestion
- destroy foreign substances
- when cell is old or injured, these rapidly destroy organelles hence theyre called suicide bags
- digest cartilages during formation of bones
17
Q
list 2 functions of centrosomes
A
- initiates and regulates cell division
- forms spindle fibres with the help of asters
18
Q
list 3 functions of plastids
A
- chromoplasts impart colour to flowers and fruits (xanthophyll: yellow, carotene:orange , red which helps in pollination of flower and dispersal of seed
- choloroplasts (green) trap solar energy for photosynthesis contain the pigment chlorophyll
- leucoplast stores starch
19
Q
list 3 functions of nucleus
A
- regulates cell function
- if removed, the cell dies
- contains chromosomes (bearers of genes)
20
Q
list 3 functions of nucleolus
A
- produces ribosomes
- participates in protein synthesis by forming and storing RNA
- dictates ribosomes to synthesise proteins
21
Q
what is the function of chromatin fibres
A
chromosomes carry genes
22
Q
list 3 functions of vacuoles
A
- store water and other substances like food and waste products
- gives turgidity to plant cells by pressing against cel wall
- contains pigments like anthocyanins etc.
23
Q
give one function of granules
A
store starch (in plant cells), glycogen (in animal cells) and fat-containing granules which serve as food for the cell
24
Q
what is self pollination
A
it is the transfer of pollen from the anther to the stigma of the same flower or to the stigma of another flower on the same plant
25
what is autogamy
when pollen is transfered from the anther to the stigma of the same flower
26
what is geitonogamy
the transfer of pollen from the anther to the stigma of another flower on the same plant
27
give 2 requirements for self-pollination to occur
- bisexuality: self pollination can occur in bisexual flowers ie flowers having both male and female organs or it can also occur in such unisexual flowers where both male and female flowers are borne on the same plant
- homogamy: the anther and stigma of a flower must mature at the same time
28
list 5 advantages of self-pollination
- it is much surer in such bisexual flowers where stamens and carpels mature at the same time
- parental characters r preserved indefinitely
- there is no wastage of pollen grains, even a small quantity will suffice
- the flowers dont need to be large and showy
- scent and nectar dont need to be produced
29
list 3 disadvantages of self-pollination
- continued self pollination, generation after generation may lead to weakening of the variety, the seeds produced are poor in quality.
- the weaker characters of the breed cannot be eliminated
- it does not yield new varieties thus there is little chance for improvement in the next generation
30
give 2 examples of self pollinating flowers
pea, pansy
31
what is cross pollination
the transfer of pollen from the anthers of a flowers of one plant to the stigma of a flower of another plant of the same species
32
give 2 examples of cross pollinating flowers
oxalis, hibiscus
33
list 3 advantages of cross pollination
- the offsprings r healthier
- the seeds produced r abundant and viable
- new varieties can be produced
34
list 3 disadvantages of cross pollination
- pollination is not always certain as an agent of pollination may not be available at that time.
- pollen has to be produced in large quantities to ensure maximum chances of pollination meaning a lot of wastage of pollen
- the process is uneconomical because the flowers have to be large, colored, scented and have to produce nectar
35
what are insect-pollinated flowers also called
entomophilous
36
list 7 characteristics of insect pollinated flowers
- the flowers r large
- they r bright colored to attract insects
- they usually emit scent to attract insects
- they produce nectar as food for insects
- they pollen grains are sticky, making it easier to carry
- the stigma is sticky and doesnt usually hang out
- the flowers tend to be in clusters to make them conspicuous
37
what are wind-pollinated flowers also called
anemophilous
38
list 8 qualities of wind pollinated flowers
- the flowers are small
- they are usually not bright colored and often dull green
- they do not produce scent or nectar
- their stamens are long and hang out to be exposed to the wind
- their anthers are large and loosely attached so even the slightest wind can move them
- pollen is produced in very large quantities
- pollen grains r light, dry and smooth so they can easily be carried away by the wind
- the stigmas are feathery and hang out to trap the pollen
39
list 5 conditions which show that nature favours cross pollination
- unisexuality: the flowers may be either male or female and they may be borne on separate plants. in this way cross pollination is the only possibility
- dichogamy: in many bisexual flowers, the anthers and stigma of the same flower mature at different times
- self sterility: this is a condition in which even if the stigma receives pollen from the anthers of the same flower, the pollen fails to undergo further growth, in such cases only the pollen from another plant of the same species can complete the process of setting the seeds
- herkogamy: in some flowers, the pollen of a flower cannot reach the stigma of the same flower
- heterostyly: in such flowers, the stigma and anthers grow at different heights which does not favor self pollination
40
explain the process from pollination to fertilization
the pollen grain on falling on the stigma is stimulated to germinate due to the secretion of sugars. Through a point in the exine, a pollen tube grows out og the pollen grain, carrying the generative nucleus and the tube nucleus, the generative nucleus divides into 2 sperm nuclei (also male gamete nuclei). The pollen tube grows through the stigma and style by dissolving the tissues with the help of enzymes and reaches the ovary. There, it pushes through the micropyle and reaches the embryo sac. The tube nucleus then disentegrates. Then the pollen tube enters one of the synergids and releases its 2 sperm nuclein, one fuses with the egg cell nucleus to form the zygote while the other fuses with the 2 polar nuclei in the centre.
41
how many nuclei are there in a germinating pollen grain
3
42
define fruit
the enlarged ripened ovary
43
define seed
ripened ovule
44
what is monocot and dicot seeds, give 2 examples for each
monocot seeds contain one ctyledon
eg: maize, grasses
dicot seeds contain two cotyledons
eg: pea, gram
45
define germination
the process of formation of a seedling developed from the embryo
46
give 3 points on germinatio
- on a dry seed. the embryo is in a state of dormancy
- the dry seeds consume oxygen and give out carbon dioxide both in extremely minute quanities and they release some heat as well
- when placed under proper conditions, the dormant embryo awakens and starts growing into a seedling
47
what type of seed is bean
dicot
48
what type of seed is maize
monocot
49
list 7 differences between bean and maize
bean has two cotyledons while maize has one cotelydon
= bean has no endosperm while maize has large endosperm
- bean has large embryo while maize has small embryo
- bean has folded plumule leaves while maize has rolled plumule leaves
- bean has large plumule, maize has small plumule
- bean has visible hilum and micropyle, maize has not visible hilum and micropyle
- in bean, seed separately contained in the fruit called pod, in maize the seed wall and the fruit wall fused to form a single grain with no separate seed
50
what is the structure of the testa
outermost hard brownish covering
51
what is the function of the testa
protects the delicate inner parts of the seed from injury and from the attack of bacteria, fungi and insects
52
what is the structure of tegmen
thin inner layer next to testa
53
what is the function of tegmen
protective in nature
54
what is the structure of hilum
a whitish oval scare on concave side of seed
55
what does hilum represent
spot where ovule was attached to ovary wall
56
what does the micropyle work
the opening through which pollen tube entered the ovule
57
list 2 functions of micropyle
seeds absorb water through the micropyle
| - provides for the diffusion of respiratory gasses for embryo
58
how many cotyledons r there in bean seed
2
59
what is the function of cotyledon bean
contains food for embryo and protects it
60
where is the embryo located bean
attached to one of the cotyledons
61
what r the 2 parts of embryo bean
radicle, plumule
62
what does the radicle later form
root
63
what does the plumule later form
shoot
64
what is the structure of the plumule
consists of a short stem with a pair of tiny leaves and a growing point between them.
65
where is the epicotyl
the region of the axis between the point of attachment of cotyledons and the plumule
66
where is the hypocotyl
the region of axis below the cotyledons
67
what do we call a grain
a single-seeded fruit where the fruit wall and seed coat r fused
68
where is the embryo maize
on one side of the grain where there is a small light colored oval area
69
list the 9 parts of maize grain
endosperm, embryo, aleurone layer, scuttelum, radicle, plumule, coleorhiza, coleoptile
70
where is the endosperm
the remaining major part of the grain outside the embryo
71
how r the endosperm and embryonic parts separated
by a thin epithelial layer
72
what is the aleurone layer
outermost layer of endosperm rich in protein
73
what r the 3 parts of the embryo maize
scutellum, radicle, plumule
74
what is the structure of the radicle
the radicle is towards the pointed end
75
what is the coleorhiza
protective sheath which encloses radicle
76
where is plumule located
towards the upper broader side of the embryonic region
77
what is the coleoptile
protective sheath which encloses the plumule
78
what are the 3 differences between hypogeal and epigeal germination
1. in hypogeal cotyledons remain underground, in epigeal cotyledons r pushed above ground
2. in hypogeal, epicotyl elongates faster, in epigeal, hypocotyl elongates faster
3. hypogeal usually happens in monocot seeds while epigeal usually happens in dicot seeds
79
what are the three conditions for germination
water
suitable temperature
oxygen
80
what r the uses of water in germination, 2 points
the seed swells and then the coat ruptures allowing the radicle to come out and form the root system
water is used for chemical reactions and for enzymes to act upon the food stored so that it may convert into a form that can be utilized by the growing embryo
81
why is suitable temperature needed for germination
both too high and too low tempeartures r unsuitable, a very low temperature inhibits the growth of the embryo and a very high temperature destroyes its delicate tissues
82
what is the optimum temperature for germination
25-35 degrees celsius
83
why is oxygen needed in germination
in germination, energy is required and that can only be available by respiration
84
give 2 reasons why seeds sown deep fail to germinate
1. no proper supply of oxygen
| 2. insufficient pushing force in the embryonic parts to break through the upper layers of soil.
85
explain the experiment to prove water is necessary for germination
take two beakers, mark them A and B. In A, place seeds of chick pea on wet cotton wool. In beaker B, place similar seeds on dry cotton wool. Keep both beakers in an ordinary room. In a day or two, seeds in A will germinate while B wont showing water is necessary for germination
86
explain experiment to prove that suitable temperature is needed for germinaton
take two beakers, A and B. Place some green gram seeds on wet cotton wool in each of them. Keep beaker A in an ordinary room and B in a fridge. In a day or two, beaker a will germinate while the seeds in beaker B may not show signs of germination or they germinate after several days showing that a suitable temp. is needed.
87
explain experiment to prove oxygen is necessary for germination
take 2 conical flasks, name them A and B, spread wet cotton wool in each flask and place some soaked gram seeds. Lower a test tube of pyrogallic acid which absorbs oxygen in flask B with a thread, arrange A in a similar manner but use plain water. Place both in an ordinary room, the seeds in flask b do not germinate like flask a (may be minimal germination due to anaerobic repisration)
88
list the 6 classes of food
carbohydrates, fats, proteins, mineral salts, vitamins, water
89
what is the function of carbohydrates
they are the principal energy sources in the body
90
list 3 roles of roughage
- they absorb a lot of water as theyre fibrous and help in keeping faecal matter soft and prevent constipation
- the movement of undigested food through the intestine becomes easier
- it stimulates muscle contraction in the intestinal wall, making the movement of faecal matter easy.
91
list 4 functions of fat
- it produces energy
- it is an importate form of food storage
- it serves as a solvent for fat-soluble vitamins
- fat under skin provides insulation
92
what is the function of protein
- growth and repair of body cells and tissues, in time of emergency they can release energy
93
cause of kwashiorkor
- caused when mothers stop breast feeding their babies at an early age leaving to a diet poor in proteins
94
list 8 symptoms of kwashiorkor
```
underweight
belly protruding out
dark and scaly skin
stunted growth
loss of appetite
repeated diaorrhea
enlarged liver and anaemia
oedema of the feet and face due to accumulation of water in tissues
```
95
what is the treatment for kwashiorkor
the child should be given a protein-rich diet.
96
who is usually affected by marasmus
infants below 1 years old
97
what is the cause of marasmus
sudden stoppage of breast feeding followed by a diet poor in energy-giving foods
98
list 6 symptoms of marasmus
- less body weight
- degenerations resulting in a weak body
- skin is loosely folded
- thin face and thin limbs
- retarded physical and mental growth
- ribs appearing prominent
99
who is affected by kwashiorkor
children of ages 1-5
100
list 5 differences between kwashiorkor and marasmus
- kwashiorkor affects children of 1-5 years of age, maramus affects infants up to 1 years
- kwashiorkor is due to deficiency of proteins, marasmus is due to deficiency of proteins, carbohydrates and fats
- there is oedema in kwashiorkor, no oedema in marasmus
- skin of kwashiorkor patient becomes dark and scaly, no darkening of skin in marasmus
- no degeneration of muscles in kwashiorkor, there is degeneration of muscles in marasmus
101
what is the 2 functions of calcium
constituent of bones and enamel
| required for muscle contraction and clotting of blood
102
what is the function of sodiun
regulates acid-base equilibrium
103
what is the function of iron
synthesis of haemoglobin associated with oxidation, reduction reactions
104
what is the function of iodine
- component of thyroxin hormonr secreted by thyroid gland
105
list 3 functions of Vitamin A
- promotes growth,
- resists infection of the skin and mucous membrane
- component of visual purple in the retinal cell of the eyes for perception of image
106
list 2 deficiency diseased of vitamin A, describe them
Night Blindness (poor vision in dim light)
xerophthalmia (dryness of the cornea and ulceration)
107
what is the function of Vitamin d
helps the body use calcium and phosphorus to form bones and teeth
108
list 2 deficiency deases of vitamin d and describe
rickets in children (bones lack calcium and become soft)
osteomalacia in adults, fractures may occur
109
what is the function of vitamin e
prevents oxidation of vitamin A
110
what is the 3 deficiency diseases of vitamin e
muscle weakness, nerve damage, immune system problems
111
what is the function of vitamin k
clotting of blood
112
what is the deficiency disease of vitamin k, describe it
haemorrhage (delay in clotting time)
113
what is the function of B12 vitamin
normal functioning of red blood cells
114
what is the deficiency disease of b12, explain
penicious anaemia ( a severe anaemia coupled with great weakness and gastrointestinal disturbance, degeneration of spinal cord.)
115
what is the function of vitamin c
promotes functioning of capillary walls
116
list 2 deficiency diseases of vitamin c, explain
- increased susceptibility to infections
| - scurvy ( spongy and bleeding gums, loosening of teeth.)
117
what is the definition of malnutrition
the condition in which a person suffers due to lack or deficiency of one or more essential elements of food.
118
what is a balanced diet
a diet which contains all the principle constituents of food in proper quantity.
119
list 5 functions of water in nutrition
- acts a solvent in the body for thousands of substances
- used to produce digestive juices
- helps in transportation of digestes foods and oyxgen throughout the body
- used in the excretion of soluble wastes
- involved in the maintenance of body temperature.
120
what is the importance of balanced diet
to get enough nutrients in good balance for functioning of body.
121
list 3 sources of calcium,
dairy foods, beans, cabbage
122
list a source of sodium
table salt
123
list 6 sources of iron
whole cereals, fish, nut, egg yolk, liver, kidney
124
list3 sources of iodine
iodised salt, water, sea foods
125
list 3 sources of vitamin A
butter, egg yolk, liver
126
list 3 sources of Vitamin d
milks, eggs, uv rays
127
list 3 sources of vitamin E
meat. milk. whole weat
128
list 1 source of vitamin k
leafy greens (cabbage and spinach)
129
list 3 sources of vit, b12
meat, milk, cereals and pulses
130
list 3 sources of vitamin c
citrus fruits, tomatoes, germinating seeds
131
what ratio is hydrogen and oxygen in, in carbs
2:1
132
how do carbs release energy
they are oxidised in cells
133
give 2 forms of carbs
sugars, starch
134
what are the 2 categories of sugar
monosaccharides, disaccharides
135
what is the formula of monosaccharides
C2H12O6
136
what is a characteristic of monosaccharides
these need no digestion and are straightaway absorbed
137
give 3 types of simple sugars
glucose, fructose, galactose
138
what is glucose known as
grape sugar
139
what is the most common and simplest sugar found in organisms
glucose
140
what do we mean when we say blood sugar level
we mean the glucose level in blood
141
what is fructose also called
fruit sugar
142
where is fructose most common
plants
143
where is galactose found
milk
144
what is the chemical formula of double sugars
c12h22O11
145
what is a characteristic of disaccharides
they require digestion to be absorbed
146
list 3 types of disaccharides
sucrose, maltose, lactose
147
what is our commercial sugar
sucrose
148
how is sucrose obtained in india
from sugarcane
149
what is sucrose made of
glucose and fructose
150
what is maltose also called
malt sugar
151
what is maltose made of
2 glucose molecules
152
what is lactose also called
milk sugar
153
what is lactose also made of
glucose and galactose
154
in what form do plants commonly store carbohydrates
starch
155
list a characteristic of starch
its insoluble
156
list 3 sources of starch
potatoes, grains, bread
157
what is the chemical formula of starch
C6H10O5)n
158
what is starch also called
polysaccharide
159
name two other insoluble polysaccharide carbs
cellulose, glycogen
160
where is cellulose found
cell walls of plants
161
what is the function of cellulose
it contributes in providing roughage
162
what is the function of glycogen
the form in which carbs r stored in animals
163
where is glycogen stored
majorly in liver and some muscles
164
what elements are fats composed of
carbon, hydrogen, oxygen
165
do fats produce less energy than carbs or more
more
166
list three foods rich in fat
butter, ghee, vegetable oils
167
what are fats and oils made up of
fatty acids and glycerol
168
what elements is protein made of
carbon, hydrogen, oxygen and nitrogen
169
which is the most essential element in proteins
nitrogen
170
list 3 examples of food rich in protein
lean meat, fish, eggs
171
define vitamins
chemical substances needed in minute amounts which help maintain a healthy body
172
what do most vitamins act as
catalysts or enzymes in essential chemical changes in the body,
173
list 2 macro nutrients
calcium, sodium
174
list 2 micro nutrients
iron, iodine
175
what is the difference between fat and water soluble vitamins
fat soluble vitamins can be stored in the body for long periods of time while water-soluble cannot
176
list 4 fat soluble vitamins
A,D,E,K
177
list 2 water soluble vitamins
B complex, C
178
what are the different types of teeth
Incisors, canines, premolars, molars
179
what are the incisors shaped like
broad and sharp cutting edges
180
what is the function of incisors
biting and cutting
181
what are canines shaped like
conical and sharply pointed
182
what is the function of canines
holding and tearing food
183
what is the structure of premolars
two cusps on its surface called bicuspid
184
what is the function of premolars
grinding and crushing
185
what is the shape of molars
larger surface than premolars
186
what is the wisdom tooth
last molar on each side of jaw
187
when do wisdom teeth last appear
age of 17-20
188
what is the dental formula of an adult
2 1 2 3 | 2 1 2 3
189
what are the three sections of a tooth
crown, root, neck
190
what is the crown
part exposed above the gum
191
what is the root of the tooth
part embedded in a cup-like socket of the jaw bone
192
what is the neck of the tooth
slight constriction between the root and the crown
193
what are the 4 parts of the tooth
enamel, dentine, cement, pulp
194
what is the hardest substance in the body
enamel
195
what is the enamel also called
ivory
196
what is the enamel
the material which covers the crown
197
what forms the bulk of the tooth
dentine
198
what is the hardness of dentine
harder than bone but not as hard as enamel
199
what is the structure of the dentine
has minute canals through which run the strands of cytoplasm of the cells in pulp cavity
200
what is cement
another bone like structure covering and fixing the root in position
201
what is the pulp
soft connective tissue contained in the central space of the tooth (pulp cavity).
202
what does the pulp consist of
blood capillaries, lymph vessels and nerve fibres which are continuous below those of the body through the opening of the pulp cavity at the base of the root
203
what are the three salivary glands
parotid glands
submandibular glands
sublingual glands
204
wher r the parotid glands located
just in front of and beneath each year
205
where are the submandibular glands locaed
lose to the inner side of the lower jaw on each side
206
where is the sublingual glands located
below the tongue
207
what is saliva
a very slightly acidic fluid containing water, salts, mucus and an enzyme salivary amilase
208
what is ptyalin
salivary amilase
209
what is the function of salivary amilase
it converts starch into maltose
210
what is the oesophagus
the tube which simply conducts the food from the throat to thr stomach
211
where is the oesophagus
it passes through the diaphragm close to the backbone
212
how is food in the oesophagus conducted
through peristalsis
213
what is peristalsis
peristalsis is the wave of constrictions caused by the circular muscles of the gut pushing food along
214
where does peristalsis occur
all regions of the gut
215
what is mucus
a slimy fluid secreted by all regions of the gut which lubricates food
216
what is the stomach
an elastic bag located below the diapghram
217
how much food can the stomach hold in an average adult
2-3 litres
218
why are stomach walls highly muscular
to churn the food thoroughly to mix with the gastric juice
219
what is the pylorus
the opening of the stomach into the intestine
220
what is a sphincter
a ring of muscles
221
what is the function of a sphincter in stomach
to keep the opening closed like a valve to prevent food passing from the stomach until it is thoroughlry churned, also prevents regurtitation from the duodenum
222
where is the cardiac sphincter
front end of the stomach
223
what is the function of the cardiac sphincter
to prevent back flow of blood into the oesophagus
224
what does the inner lining of the stomach secrete
gastric juice
225
what does gastric juice contain
water, some salts, hcl and an enzyme called pepsin
226
what r the 2 functions of gastric juice
- it kills any germs which may have entered along with the food
- it activates pepsin to act on proteins, pepsin digests proteins
227
what percent of protein does pepsin digest
20%
228
how is pepsin formed
pepsinogen is changed into pepsin by the hydrochloric acid
229
how are peptides formed
pepsin digests proteins into peptides
230
how is rennin formed
prorennin is changed into rennin by hcl
231
how is paracasein formed
casein is changed to paracasein by rennin
232
where is rennin found
in babies
233
how long does food stay in the stomach
3 hours
234
what is chyme
the pulp-like form attained by the food when it stays in the stomach for three hours.
235
what is the length and width of the small intestine
7 meters long, 2.5 cm wide
236
what are the 3 sub-divisions of the small intestine
duodenum
jejunum
ileum
237
where is the duodenum located
short upper part next to stomach
238
where does the common bile duct open into
duodenum
239
how long is the jejunum
12 finger widths
240
how long is the jejunum
2 metres
241
which part of the intestine is often found empty after death
the jejunum
242
how long is the ileum
4 metres
243
what are villi
number of tiny finger like projections which the inner lining of the ileum are made into
244
how does the villi help
they increase the inner surface area of the intestine which facilitates the absorption of digested food
245
what are between villi, what do those things do
small holes through which intestinal juice secreted by glandular cells is poured into the lumen of the intestine
246
what is the villus covered by
single cell thick epithelium
247
what are the 4 components inside the villus
an artery, a vein, inter-connecting capillaries, a lymph vessel called lacteal
248
what are the two functions of the mall intestine
both digestion and absorbtion
249
what are the 2 digestive juices received in the duodenum
bile, pancreatic juice
250
what are the 4 adaptations of ileum for absorption of digested food
1. it is very long and more surface area is provided
2. the large number of villi increase surface area too
3. single celled epithelium
4. it is narrow which slows the movement of food which allows absorption
251
list 2 physical qualities of bile
yellowish-green watery fluid
252
where is bile produced
the liver
253
how is bile transported
hepatic duct
254
how is the common bile duct formed
the hepatic duct is joined by the cystic duct
255
what happens to bile
it may flow directly into the duodenum or get temporarily stored in the gall bladder
256
how does bile gain its color
it is due to pigment (biliverdin, bilirubin)
257
how is biliverdin and bilirubin produced
by the breakdown of dead and wornout rbc
258
what are the two roles of bile
- acidic chyme is converted by NaHCO3 (sodium bicarbonate) in bile to alkaline chyme
- fat is converted into emulsified fat by bile salts.
259
where is pancreatic juice produced
produced in a whitish gland, pancreas, located behind the stomach
260
list the 3 kinds of enzymes in pancreatic juice
amylopsin, trypsin, steapsin
261
list the role of pancreatic enzymes in 4 points
trypsinogen is activated into trypsin by enterokinase
- proteins and peptides are turned into smaller peptides and amino acides by trypsin
- leftover starch is turned into maltose by amylopse
- emulsified fat is turned into fatty acids + glycerol by steapsin
262
what is amylopsin also called
pancreatic amylase
263
what are the 5 changes in intestinal juice
- remaining peptides are turned into amino acids by erepsin or peptidases
- maltose is digested into glucose by maltase
- sucrose is split into glucose + frictose by sucrase
- lactose is digested into glucose and galactose by lactase
- emulsified fat is digested into fatty acids and glycerol by lipase
264
how are amino acids absorbed
they have small-sized molecules which are absorbed through the thin epithelium of the villi, carried to the liver by the hepatic portal vein.
265
how are the fatty acids and glycerol absorbed
they are absorbed into the lacteals to enter the lymphatic system.
266
how long is the large intestine
1.5 metres long
267
what are the three parts of the large intestine
caecum. colon, rectum
268
what is the caecum, where is it located
a small, blind pouch situated at the junction of the small and large intestines.
269
what is the vermiform appendix
a functionless organ shaped like a narrow worm shaped tube projecting from the blind end of the caecum
270
what causes appendicitis
the inflamation of the vermiform appendix
271
how long is the colon
a little more than a metre
272
where is the colon located
it passes up the abdomen on the right, crosses to the left just below the stomach and down on the left side
273
how long is the rectum
about 15 cm long
274
where does the rectum kpen
at the anus
275
why does the anus have sphincters
to keep it closed expect when passing bowels
276
what does the mouth secrete
saliva
277
what does the stomach secrete
gastric juice
278
what does the duodenum secrete
bile and pancreatic juice
279
what does the ileum secrete
intestinal juice
280
what is the function of the large intestine
it absorbs much water and mostly undigested material. after much water is absorbed. the content becomes semi-solid faeces and is expelled at intervals
281
what is defaecation
the expulsion of undigested remains of food
282
what is assimilation
the conversion of absorbed digested food into body material.
283
what is glycogenesis
the conversion of excess glucose into glycogen which can be temporarily stored.
284
what is glycogenolysis
the reconversion of glycogen into glucose by the liver which puts it back in the blood circulation
285
why is glucose required in the body
as a source of energy in cellular respiration and also in the synthesis of certain compounds
286
what are the building blocks of protein
amino acids
287
what is deamination
the process by which excess amino acids are broken down in the liver through the removal of the nitrogen-containing amino group which is converted into urea for extraction
288
how much does the liver weigh
1.5 kg
289
what is the color of the liver
reddish-brown
290
where is the liver located
the upper right side of the abdomen, just below the diaphragm
291
explain test for glucose
a little glucose is added to fehlings solution in a test tube, tilt the test tube away from you and heat it over a flame until bubbles begin to appear but dont allow it to boil over. The color changes from blue-green to brick red with the appearance of a precipitate. A small piece of apple or grape will give the same result.
292
explain test for starch
a little starch powder is shaken in a test tube with some water and then boiled to make a solution. When the solution is cold, add a few drops of iodine. The starch solution would turn blue-black indicating the presence of starch
293
explain test for proten
place a piece of hard-boiled egg-white in a test tube. Add a few drops of concentrated nitric acid enough to immerse the sample of food. Heat the test tube gently, then cool it by placing it under tap water and add ammonium hydroxide. You would notice the color changes from white to yellow under heating and then from yellow to orange upon adding ammonium hydroxide
294
explain test for fats and oils
rub a piece of groundnut, walnut, a piece of butter on a plane paper. The spot rubbed turns translucent especially when viewed against light,
295
What is pollination in the same flower, same plant but diff flower, diff plant called respectively
Autogany
Geitonogamy
Allogamy
