Multicellular Organisms Flashcards
1
Q
How are new cells formed?
A
Mitosis is the name given to the process of cell division.
2
Q
Why do new cells need to be produced?
A
For growth
& Repair of damaged cells
3
Q
What part of the cell controls mitosis?
A
The nucleus controls mitosis.
4
Q
What does the nucleus contain?
A
Chromosomes
5
Q
How many chromosomes does a human cell contain?
A
46
6
Q
What is one strand of a duplicated chromosomes called?
A
One chromatid
7
Q
What is the centre of a duplicated chromosome called?
A
A centromere
8
Q
What happens during mitosis?
A
Parent cell with four chromosomes
Chromosomes are copied. They are joined in the centre by a centromere and are called chromatids.
Chromatids become shorter and thicker and become visible. The nuclear membrane disappears.
Chromatids line up along the equator and are attached by spindle fibres.
The spindle fibres shorten pulling the chromatids to opposite poles.
Nuclear membrane does around each nucleus.
Cytoplasm divides and so the cell is divided into two identical daughter cells contains exactly the same number of chromosomes as the parent cell.
9
Q
What happens to the number of chromosomes after mitosis?
A
Body cells are diploid meaning that they have 2 matching sets of chromosomes.
Mitosis maintains the diploid chromosome complement by producing two diploid daughter cells.
Meaning that all body cell have the same chromosome complement.
10
Q
What are stem cells?
A
Stem cells are unspecialised cells in animals.
They are also single cells that can replicate itself or differentiate into many cell types.
11
Q
What can stem cells divide in order to do?
A
Self-renew
Become different types of cells
12
Q
What are stem cells involved in?
A
Growth and repair.
13
Q
What are some of the uses for stem cells?
A
Replacement body organs (heart, trachea)
Bone marrow transplants
Skin grafts
14
Q
What are all living organisms made up of?
A
Cells
15
Q
How can cells have different functions?
A
Different cells have different structures to allow them to carry out different functions.
These cells are called specialised cells.
16
Q
What is the function of an egg cell?
A
Provides a food source for cell division after fertilisation.
17
Q
What is the function of the sperm?
A
Provides energy to swim to the egg
Allows it to swim/move to the egg
18
Q
What is the function of the neurone?
A
Transmits nerve impulses
Communication with other neurones
19
Q
What is the function of the red blood cell?
A
Increase the surface area
carry oxygen
To carry more oxygen
20
Q
What is the function of the root hair?
A
Increase the surface area for the absorption of water
21
Q
What is the function of the palisade mesophyll?
A
Main site of photosynthesis
22
Q
Do specialised cells carry out every function required for life?
A
Specialised cells in animals and plants lead to the creation of tissues and organs.
23
Q
What are tissues and organs?
A
Tissues are a group of specialised cells that preform one function.
An organ is a structure made up of several different tissues that preform different functions.
24
Q
What do groups of organs do?
A
Groups of organs work together to form systems.
25
What is the order do cells, tissues and organs go in?
Cells —> tissues —> organ —> organ system
26
What is the function of the cerebrum?
Memory, imagination, reasoning, conscious thought and intelligence.
27
What is the function of the cerebellum?
Controls balance and muscular coordination.
28
What is the function of the medulla?
Controls the rate of the breathing and heart
29
Where does learning take place?
Learning memory and high-level reasoning takes place in the cerebrum.
30
What are the three levels of memory?
Sensory
Short- term
Long- term
31
What is the internal communication required for?
Survival of a multicellular organism.
32
What can cells in multicellular organisms not do?
They can not work independently.
33
What is a neurone and what does it do?
A neurone is a nerve cell
Electrical impulses carry messages along the neurone
34
What are the three neurone?
Sensory neurone
Inter neurone
Motor neurone
35
What does the sensory neurone do?
Receives information from the receptor.
Passes the information to the CNS
36
What does the inter neurone do?
Receives information from sensory neurone
Passes information to motor neurone
37
What does the motor neurone do?
Receives information from the CNS
Passes information to effectors which produce a response.
38
What is an effector?
The part of the body that produces responses they can either be:
Muscles contracting
Glands which produce hormones
39
What type of response is muscles contracting?
Rapid response
40
What response is glands producing hormones?
Slow response
41
What are synapses?
Gaps in between neurone are called synapses
42
What happens at the end of a neurone?
Electrical impulse reach the end of a neurone chemicals are released from it.
43
What does a synapses do?
When chemicals are released from the end of a neuron these chemicals transfer messages between neuron at synapses.
44
What is the nervous system composed of?
The central nervous system (CNS) and the nerves.
45
What is the CNS (Central Nervous System) composed of?
The brain and the spinal cord.
46
What is a reflex action?
A reflex action is a rapid, automatic response by the nervous system.
They are involuntary and do not involve the brain.
47
How does a reflex action occur?
Information is passed to the inter neuron in the spinal cord which sends the information between the sensory and motor neurons.
48
What are the neurons that act to produce a reflex action called?
Reflex arc.
49
What is the process of the reflex arc?
Stimulus —> receptors in sensory organs detect input/stimuli —> sensory neuron —> inter neuron —> motor neuron —> effectors (muscle and gland) —> response
50
What would happen if there was a delay before the response happened in the reflex arc?
Reflex actions protect the body from further damage by allowing the body to react quickly to stimuli.
51
What are some examples of reactions to a stimuli?
Immediately pulling hand away from something hot or sharp
Blinking of object comes towards eyes
Coughing if food goes down the windpipe
52
What is a hormone?
Hormones are chemical messengers
53
What is endocrine gland?
Releases hormones into the blood stream.
54
What are hormones specific to?
Target tissue
55
How do hormones work?
Target tissues have cells with complementary receptor proteins for specific hormones, so only that tissue will be affected by the hormones.
56
If the tissue does not have the correct receptor for a hormone what happens to the tissue?
It is unaffected
57
What happens if blood glucose levels are too high?
If blood glucose levels are too high, then the water concentration of blood falls and will stop cell reactions from occurring.
58
What happens if blood glucose levels are to low?
The body cells will not get enough glucose and will not be able to release enough energy.
59
How is blood glucose level controlled if it’s to high?
Increase in blood glucose—> pancreas detects the change and released more insulin —> liver changes glucose into glycogen
60
How is blood glucose level controlled if it’s to low?
Decrease in blood glucose—> pancreas detects the change and releases more glucagon —> liver changes glycogen into glucose
61
What condition do people suffer from if they cannot control blood glucose levels?
Diabetes due to the body failing to release insulin or not responding to insulin
62
What are sex cells called?
Gametes
63
What are the differences between sperm and egg cells?
Sperm- small, tail to swim, small food store, millions produced
Egg- large, does not move, large food store
64
Where are the sex cells produced?
Tested are the site of sperm production
Ovary are the site of egg production
65
What happens when the spent and egg meet?
```
23 chromosomes from father
23 chromosomes from mother
|
|
Zygote with 46 chromosomes
```
66
What are diploids?
Body cells are diploid- they have 2 sets of chromosomes
67
What are gametes?
Gametes are haploid- they have 1 set of chromosomes
68
What is fertilisation?
The fusion of the nucleus of the two haploid gametes to produce diploid zygote.
The zygote then divides to form an embryo.
69
What is a fertilised egg cell called?
Zygote
70
Where does fertilisation?
It occurs in the oviduct
71
What parts in a flower are there?
```
Stigma
Style
Ovary
Ovules
Anther
Filament
Petal
Sepal
Stem
```
72
What are the female sex cell in a plant?
Ovules which are produced in the ovary
73
What is the male sex cell in a plant?
Pollen and it is produced in the anther.
74
How does fertilisation occur in plants?
Pollen grains need to be transferred from the anther to the stigma
This is called pollination
Then the pollen forms a pollen tube
Once on the stigma pollen grains form a pollen tube which grows down through the style until it reaches the ovary
Nucleus of the pollen grain travels down the pollen tube and fuses with an ovule
This causes fertilisation
75
Why do children look similar to their parents?
Due to the passing of genetic information in the form of genes
76
What does combining genes from two parents do?
Why does this happen?
Contributes to the variation within a species.
This happens due to a new combination of genes.
77
What is discrete variation?
What is it controlled by?
A characteristic where measurements fall into distinct groups.
These characteristics are controlled by single gene inheritance.
78
What is continuous variation?
What is it controlled by?
A characteristic which shows a range of values between a minimum and a maximum
These characteristics are controlled by polygenic inheritance.
79
What does polygenic mean?
Several genes
80
What are some examples of discrete variation?
```
Ability to roll tongue
Blood type
Ear lobes
Pea plant flower colour
Maize grain colour
Pea plant seed shape
```
81
What are some examples of continuous variation?
```
Height
Body mass
Index finger length
Leaf length
Tree height
Shoot length
```
82
Which type of variation is more common?
Most individuals phenotype are polygenic and show continuous variation.
83
What is polygenic inheritance?
Several genes interact to determine one characteristic
84
What are some examples of polygenic inheritance?
Skin colour
Height
Seed mass
85
What are genes?
A gene is a section of DNA which controls the inherited characteristic of an organism.
86
How many genes control a characteristic?
Two forms of a gene, each parent contributing one of the two forms
87
What are alleles?
Different forms of the same gene
88
What are some examples of genes?
```
Blood group
Flower colour
Colour
Seed colour
Coat colour
Seed shape
```
89
What are some examples of alleles?
```
A,B,AB or O (blood group)
Purple or white (flower colour)
Speckled or Melanie (flour on peppered moth)
Yellow or purple (seed colour)
Black or brown or golden (coat colour)
Round or wrinkled (seed shape)
```
90
If there are two alleles which one shows in our appearance?
A dominant allele will always show up in an individuals appearance.
A recessive allele is always hidden by s dominate allele unless it is paired with another recessive.
91
What is a phenotype?
The phenotype is the physical appearance of an organisms inherited characteristic.
92
What is a genotype?
The set of alleles that are present in an organism.
93
If the allele is dominate what is used?
A capital letter
94
If the allele is recessive what is used?
A lower case letter
95
What does homozygous mean?
Both alleles are the same
96
What does heterozygous mean?
Both alleles are different
97
What are family trees?
A family tree can be used to find out individual phenotype and genotypes
98
What term is used to describe individuals when they always pass on the same genotype (another name for homozygous)?
True breeding
99
What is a monohybrid cross?
A monohybrid cross looks at the inheritance patter of one gene through a number of generations
100
What does P...F1...F2 mean?
```
P= parents
F1= first generation
F2= second generation
```
101
What happens when two opposing true breeding genotypes cross?
All the offspring will be heterozygous
102
Why would the predicted ratio not always be observed?
The predicted ratio is not always observed as fertilisation is random or the sample size may not be big enough
103
What is the equation for photosynthesis?
Carbon dioxide + water —> glucose + oxygen
104
Where does photosynthesis take place.
The leaf of the plant (in the chloroplast which is filled with chlorophyll)
105
What are the plants organs?
Roots
Stems
Leaves
106
What does a leaf need?
A way to transport water to the leaf and glucose to other parts of the plant.
A way to exchange carbon dioxide and oxygen
The ability to absorb light energy efficiently
107
What are the structure of the leaf?
```
Waxy cuticle
Upper epidermis
Palisade mesophyll
Spongy mesophyll
Vein
Moist air space
Stoma
Guard cell
Lower epidermis
```
108
What is the function of the waxy cuticle?
Waterproof layer to prevent evaporation of water
109
What is the function of the epidermis?
Protective layer transparent to let light through
110
What is the function of the vein?
Contains xylem and phloem which control transport of water and sugar
111
What is the function of the mesophyll cells?
Layers of green cells which take in carbon dioxide and give out oxygen during photosynthesis
112
What is the function of the moist air space?
Large moist area for carbon dioxide to dissolve before diffusion
113
What is the function of the stomata?
Pore in lower leaf surface which allows entry of carbon dioxide
114
What is the function of the guard cells?
Pair of cells surrounding stomata which control gas exchange
115
How are substance transported in plants?
Through the phloem and xylem
116
How is the structure of the phloem cell suited to its function?
Living
Cytoplasm is continuous due to the holes in the end plates (allows sugar to transport)
Sieve tunes lack a nucleus so are controlled by the companion cell
117
What is the phloems function?
To transport sugar up and down the plant
118
Why do plants need sugar?
Plants need sugar as a source of energy
119
Where is sugar made in plants?
Sugar is the product of photosynthesis
It is transported in both an upwards and a downwards direction
120
How is the structure of the xylem cell suited to its function?
Dead
Rings or spiral of lignin for support
Function is to transport water and minerals upwards
121
What does lignin allow the xylem to do?
To withstand the pressure changes as water moves through the plant
122
Why do plants need water?
Photosynthesis
| Transporting materials e.g minerals
123
Where does water move from in a plant?
The roots
124
How does water enter the roots?
Through root hair cells by the process of osmosis
125
What do root hairs increase?
The surface area which increase the absorption of water.
126
Equation process of water transports in plants?
Root hairs absorb water
Water travels up xylem
Water arrives at the mesophyll cells (in the leaf) for photosynthesis
Water is lost through the leaves by transportation
127
How is water lost from a leaf?
Transportation is the loss of water through leaves
128
What factors effect the rate of transportation?
Wind speed
Humidity
Temperature
Surface of a leaf
129
Water is lost by...what in the stomata?
What consoles the opening and closing of the stomata?
Evaporation
Guard cells
130
What information do you need to know about guard cells?
Control opening and closing of stomata
Found on the lower epidermis
131
Why does the opening and closing of the stoma occur?
They occur due to changes in turgor of the guard cells
132
What substance are transported in the blood?
Blood transports nutrients, oxygen and carbon dioxide
133
What are the nutrients the blood transports?
Glucose and amino acid
134
What does the blood consist of?
Plasma
Red blood cells
White blood cells
135
What is the main function of the red blood cell?
Transport oxygen around the body
136
How are red blood cells suited to their function?
The are;
Biconcave
Contain haemoglobin
Have no nucleus
137
Biconcave does what exactly?
Increase the surface area of the red blood cell
138
The red blood cell having no nucleus does what exactly?
Helps it transport more oxygen
139
Why does the red blood cell contain haemoglobin?
To carry oxygen
140
How is oxygen transported around the body?
Haemoglobin combines with oxygen when the concentration of oxygen is high. This happens in the lungs.
141
What does haemoglobin + oxygen form?
Oxyhemoglobin which is bright red
142
Equation for haemoglobin and oxygen?
Haemoglobin + oxygen —> oxyhemoglobin
143
What does haemoglobin releases when oxygen concentration is low?
It releases oxygen, this happens in the respiring tissue
144
What happens when oxyhemoglobin disassociates?
It forms oxygen and haemoglobin which is dark red in colour.
The oxygen diffuses into the cells
145
The equation of oxyhemoglobin disassociating?
Oxyhemoglobin—> haemoglobin + oxygen
146
What is the function of white blood cells?
White blood cells are part of the immune system, they are involved in destroying pathogens.
147
What are pathogens?
Diseases-causing micro-organisms such as bacteria, viruses and fungi
148
What are the two main types of cells involved in destroying pathogens?
Phagocytes and lymphocytes
149
What are phagocytes?
Carry out phagocytosis by engulfing pathogens
150
What are lymphocytes?
Some lymphocytes produce antibodies which produce pathogens.
Each antibody is specific to a particular pathogen.
151
What are the three blood vessels?
Arteries
Capillaries
Veins
152
The function of arteries?
Carry blood under high pressure away from the heart
153
What are the features of the arteries?
Thick, muscular wall
| Narrow central channel
154
What is our pulse?
Blood being pushed into the arteries by the heart casusing the arteries to swell
155
Functions of the vein?
Carry blood under low pressure back towards the heart
156
What are the features of vein?
Wider central channel
Thin muscular wall
Valve to prevent back flow of blood
157
What is the function of the capillaries?
The exchange of materials occurs.
158
What does the capillaries structure make it easier to do?
Easier for substances to pass between the blood and body cells.
159
What are the features of the capillaries?
Small cavity
| Thin walled
160
What do capillaries form?
Networks at tissues and organs
161
Why do capillaries form networks?
To allow efficient exchange of materials at a cellular level
162
What feature do network capillaries have?
Large surface area
163
What is the function of the heart?
To pump blood around the body
164
What is the heart made of?
Muscle
165
How many chambers does the heart have?
4 chambers
166
Why does the heart have valves?
To prevent back flow of blood
167
On the right side of the heart there is?
The superior vena cava
Pulmonary artery
Right atrium
Right ventricle
Inferior vena cava
168
On the left side of the heart there is?
Aorta
Pulmonary vein
Left atrium
Left ventricle
169
The right side of the heart has what valves?
Atrioventricular valves (AV)
Tricuspid valve
Mitral valve
170
The left side of the heart has what valves?
Semilunar valves (SL)
Pulmonary valve
Aortic valve
171
Why is the left ventricle wall thicker than the right ventricle?
Because the left side of the heart pumps blood around the entire body.
172
Where does oxygenated blood return from?
The lungs and contain high concentration of oxygen
173
Where does deoxygenated blood return form?
The body and contains a low concentration of oxygen
174
Where does the right ventricle pump blood too?
The lungs
175
What is the function of the coronary artery?
Supplies the heart with oxygenated blood
176
What happens if the coronary artery becomes blocked?
Blood flow is prevented and a heart attack will occur.
177
What are the lungs?
Are gas exchange organs
178
What are the parts of the respiratory?
```
Trachea
Lungs
Bronchi
Bronchi (bronchus singular)
Bronchioles
Alveoli (air sacs)
Blood capillaries
```
179
Describe the passage of oxygen into our body?
Air enters mouth/nose
Air moves down trachea
Air moves through bronchus
Air moves through bronchioles
Air enters alveoli
Oxygen moves into blood and carried around the body in the bloodstream where it will enter the body cells
180
What do our cells use oxygen for?
Oxygen and nutrients must be absorbed into the bloodstream to be delivered to cells for respiration.
181
Which gas is a product of respiration?
Carbon dioxide must be removed form cells into the bloodstream
182
Describe the passage of carbon dioxide out of our body?
Carbon dioxide moves from body cells into blood stream to be carried to the lungs
Carbon dioxide enters alveoli
Carbon dioxide moves up though the bronchioles
Carbon dioxide moves up through the bronchus
Carbon dioxide moves up the trachea
Carbon dioxide exists nose/mouth
183
Why do lungs have rings of cartilage?
Rings of cartilage keep the main airways open
184
Where in the lungs does gas exchange occur?
In alveoli
185
What does large number of alveoli provide?
Large surface area for the exchange of gases
186
What happens in the alveoli with oxygen and carbon dioxide?
Oxygen and carbon dioxide exchanged at the alveoli
Oxygen diffuses from the lungs to the blood capillaries
Carbon dioxide diffuses from the blood capillaries to the lungs.
187
How are the alveoli specialised to allow the efficient exchange of gases?
Large surface area
Thin walls
Extensive blood supply
Short distance
188
Why do the alveoli have a large surface area?
To allow as much gas exchange as possible
189
Why do the alveoli have thin walls?
To allow quick diffusion of gases
190
Why do the alveoli have an extensive blood supply?
To transport the materials to and from the alveoli
191
Why do the alveoli have a short distance from the blood capillary?
To allow fast diffusion of gases
192
What are the three main food groups and what are they broken down into?
Carbon dioxide- glucose
Protein- amino acids
Fats- fatty acids glycerol
193
What is digestion?
The break down of large insoluble food molecules into small soluble molecules by digestive enzymes
194
What is the bodies digestive system?
Alimentary canal (gut)
195
What are some of the structures found in the digestive system?
Mouth- teeth and silvery glands
Oesophagus
Stomach
Liver
Gall bladder
Pancreas
Small intestine
Large intestine
Appendix
Rectum
Anus
196
What structure in the digestive system absorbs the products of digestion?
Nutrients from food are absorbed in the small intestine.
197
What does the small intestine consist of?
Projections called villi
198
What does the large number of thin walled villi provide?
Large surface area
199
How are the villi specialised to allow efficient absorption of molecules?
Large surface area
Thin walls
Extensive blood supply
200
Why do the villi have large surface area?
To allow as much absorption as possible
201
Why do villi have thin walls?
To allow the quick absorption of nutrients
202
Why do villi have a extensive blood supply?
To transport glucose and amino acids around the body
203
What does lacteal absorb?
Absorb fatty acids and glycerol
204
What do blood vessels in the villi do?
Absorb glucose and amino acids
205
What features do the small intestine have in common with alveoli?
They both have;
Large surface area
Thin walls
Extensive blood supply
Which increase the efficiency of absorption
