IB BIOLOGY Flashcards
0
Q
What is the name and role of NADH + H+ ?
A
- Nicotinamide adenine dinucleotide dehydrogenase (NADH)
- Hydrogen-carrying coenzyme/electron donor.
- NADH oxidises into NAD and liberates H+ and highly energised electrons in the beginning of electron transport chain.
- Hydrogen-carrying coenzyme/electron donor.
1
Q
What are the 5 main parts of a chloroplast ?
A
Double membrane Starch Grain Grana Thylakoid Stroma
2
Q
What are the 4 steps within Glycolysis ?
A
- Phosphorylation
- Lysis
- Oxidation
- ATP formation
3
Q
What is the role of Thylakoids in chloroplasts ?
A
- Site of light dependent reactions
- large surface area to maximise light absorption
- Small space inside thylakoids allows for protein accumulation.
- the interior is acidic (Ph=4) high proton concentration allowing for chemiosmotic gradient
4
Q
What does the entire aerobic respiration process have to intent ?
A
MAKE ATP SYNTHETASE WORK
ex. Humans need to breathe oxygen to maintain that hydrogen concentration gradient and keep ATP synthetase working.
5
Q
What is the Krebs Cycle ?
A
Each acetyl group (CH3CO) formed in the link reaction yields : (1 turn of cycle) 2 CO2. 3 times NADH+ H+ 1 time FADH2 1 time ATP
6
Q
What are the facts about stroma in chloroplasts ?
A
- site of light INDEPENDENT reactions
- stroma ph = 8/ basic when calvin cycle enzymes function optimally.
7
Q
What is the role of Oxygen ?
A
- O enters aerobic respiration in final phase (ETC)
- responsible for maintenance of hydrogen concentration gradient between spaces separated by inner mitochondrial membrane
- Gradient promotes functioning of ATP synthetase (enzyme) and thus the phosphorylation of ADP to form ATP
- O Binds to free hydrogens to form water = hydrogen consumption keeps the hydrogen gradient and the proton traffic through the ATP synthetase.
8
Q
Explain what Link reaction is :
A
In aerobic respiration (in mitochondria in eukaryotes) ech pyruvate is decarboxylated (CO2 removed).
The remaining 2carbon molecules (acetyl group) reacts with reduced coenzyme A, and, at the same time, one NADH+H+ (proton) is formed.
9
Q
What is the relationship between the structure of the mitochondrion and its function ?
A
- Mitochondria are organelles that are involved in aerobic respiration in the cell.
- On their inner membrane (cristae) and in their fluid matrix are enzymes and materials needed for all stages of aerobic respiration = which produces ATP
- The cristae are folded to create more surface are so as to create more space for the electron transport chain to occur.
- There is so small space between inner and outer membranes for accumulation of protons.
10
Q
What does reduction involve ?
A
- Gain in electrons
- Loss of oxygen
- gaining Hydrogen
11
Q
What are the 3 main steps of Cell respiration ?
A
- Glycolysis
- Krebs Cycle
- Electron Transport Chain
12
Q
What does oxidation involve ?
A
- Loss of electrons from an element
- Gaining oxygen
- Losing Hydrogen
13
Q
What does the chloroplast membrane do ?
A
It is a double membrane regulating internal conditions
14
Q
What happens in the Electron Transport Chain ?
A
- Electrons from NADH and FAD2 which are donated are passed through an electron transport chain to oxygen
- Which then combines with hydrogen to form Water
- Multi step reduction-oxidation (redox) process that occurs on the mitochondrial inner membrane
15
Q
Describe the process of Glycolysis
A
- In the cytoplasm, one hexose (6 carbon) is converted into 2 three-carbons atom compounds (pyruvates) = GAIN of 2ATP and 2 NADH+ H+.
- In Phosphorylation, ATP loses 1 of its phosphates to the sugar to become ADP. This added phosphate makes sugar unstable and allows it to be broken down more easily.
- In Lysis, the 6 carbon molecule is split by enzymes into 2 three-carbon molecules of PGAL/G3P/TP. Each PGAL is then oxidised (Hydrogen ion removed and added to an ion carrier NAD+), which makes 2 molecules of NADH
16
Q
What are the 3 facts about thylakoid membranes ?
A
- Hold photosystem pigments
2. Pigments anchor in thylakoid membrane by hydrophobic/Hydrocarbon tails
17
Q
What are tumours the product of ?
A
uncontrolled cell division that occur in any organ or tissue.
18
Q
What is cytokinesis in 2 words ?
A
cellular division
19
Q
What are the 6 steps in Telophase ?
A
- Sister chromosomes have arrived at poles
- Spindle disappears
- Centrioles replicate
- Nuclear membrane becomes visible
- Nucleolus becomes visible
- Chromosomes decondense becoming chromatin
20
Q
Recap of Prophase
A
The phase in mitosis in which the duplicated chromosomes condense, the nuclear envelope dissolves and centrioles divide and move to opposite ends of the cell.
21
Q
What is interphase in a sentence ?
A
Active period in the life of a cell when many metabolic reactions occur, including protein synthesis, DNA replication and an increase in the number of mitochondria and/or chloroplasts.
22
Q
What are the 3 steps in Interphase ?
A
- G1 : Growth, protein synthesis, increase in the number of mitochondria and/chloroplasts
- S : DNA replication
- G2 : Growth,protein synthesis, preparation for mitosis/cytokinesis.
23
Q
Recap of Interphase
A
The phase of a cell’s life where DNA is repicated
24
Recap of Anaphase
The phase in mitosis in which chromosomes begin to separate.
25
What are the 5 main steps in Prophase ?
1. Chromosomes condense by supercoiling becoming visible.
2. Centrioles move to opposite poles
3. nucleolus disappears
4. Nuclear membrane disappears
5. Microtubular spindle apparatus form at each poles.
26
What 4 other processes involve mitosis ?
1. Growth
2. Embryonic development
3. Tissue repair
4. Asexual reproduction
27
How does mitosis produce 2 genetically identical nuclei ?
1. DNA replication during S phase of interphase produces 2 identical copies of DNA.
2. Identical sets of DNA are attached to each other as sister chromatids of each of the cell's chromosomes.
3. Mitosis segregates the two chromatids of each chromosome to opposite poles, forming two identical nuclei, each with one complete copy of the original DNA.
4. Cytokinesis separates the two daughter nuclei into identical daughter cells.
28
What is mitosis in 2 words ?
nuclear division
29
What are the 2 main steps in Metaphase ?
1. Spindle microtubules attach to chromosomes centromeres
| 2. Chromosomes move to the equator
30
Give a complete definition of Mitosis
Mitosis is the duplication and division of a eukaryotic cell's nucleus and nuclear material (DNA). The stages of mitosis are : Interphase, Prophase, Metaphase, Anaphase and Telophase.
31
What are the 2 steps in Anaphase ?
1. Centromeres split as spindle microtubules pull chromatids to opposite poles (after centromeres split sister chromatids become sister chromosomes)
2. Sister chromosomes move to opposite poles as microtubules shorten.
32
Recap of Metaphase
The phase in mitosis in which chromosomes line up at the equator (central plane of the cell).
33
What are the 5 phases of cell division ?
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. telophase
34
Recap of telophase
The last phase, when the chromosomes migrate to opposite ends of the cell, two nuclear envelopes form, and the chromosomes uncoil.
35
List the 6 functions of membrane proteins
1. Hormone binding sites
2. Immobilised enzymes
3. Cell adhesion
4. Cell to cell communication
5. Channels for passive transport
6. Pumps for active transport
36
What is the composition of a plant cell wall ?
Cellulose microfibrils
37
What does Protein synthesis do in the transport of material in a cell ?
RER produces proteins which travel through the lumen (gap in tube) of the ER.
38
What are the 5 main parts of a membrane ?
1. Phospholipid bilayer
2. Cholesterol
3. Glycoproteins
4. Integral proteins embedded in the phospholipid of the membrane.
5. Peripheral proteins attached to the phospholipid surface
39
What are the main features of the phospholipids (head) ?
1. Polar
2. Hydrophilic
3. They make the outside of the phospholipid layer
40
What is simple diffusion ?
Travelling directly through the membrane if they are small and uncharged, thus avoiding repulsion by the hydrophobic, non polar tails of phospholipids in the middle of the membrane.
41
Explain how phospholipids work to form a membrane ?
Because one end of the phospholipid is Hydrophilic and the other is Hydrophobic, they naturally form bilayers in which the heads are facing outwards and the tails are facing inward.
STABLE STRUCTURE IS FORMED
42
What are the 3 main parts of a plant cell that animal cells lack ?
1. Cellulose wall
2. chloroplasts
3. Large central vacuole
43
How are vesicles transported ?
Membrane produced by the RER flows in the form of transport vesicles to the Golgi, carrying proteins within the vesicles.
44
What are the 2 main facts about protein pumps ?
1. Integral protein pumps embedded within membrane
| 2. Specific to molecule transported.
45
How do protein pumps get the energy from ?
1. usually provided by ATP
| 2. Often by phosphorylating the protein pump as ATP is hydrolysed.
46
How does the modification process work ?
Golgi apparatus modifies proteins produced in ER
47
What are the 3 the function of a cell wall ?
1. Provides physical protection
2. Prevents excessive water uptake precluding bursting in hypotonic environment
3. produces turgor pressure which holds whole plant up against the force of gravity.
48
What is facilitated diffusion ?
Travelling through special transport proteins, if they match the shape and charge requirements to fit through the channels provided by the transport proteins.
49
What is exocytosis ?
Vesicles then fuse with plasma membranes, releasing their contents outside the cell.
50
How are proteins transported to the membrane ?
Golgi pinches off vesicles that contain modified proteins and travel to the plasma membrane.
51
Define "osmosis"
The passive movement if water molecules across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration.
52
How does the fluidity of the membrane allows it to change shape, break and reform during endocytosis and exocytosis ?
1. Lipids move laterally in a membrane, but flip flopping across a membrane is rare .
2. Unsaturated hydrocarbon tail of phospholipids have kinks that keep the molecules from packing together, enhancing membrane fluidity.
3. cholesterol reduces membrane fluidity by reducing phospholipids movement at moderate temperatures but it also hinders solidification at low temperatures.
53
Define "diffusion"
The passive movement of particles from a region of higher concentration to a region of lower concentration.
54
What is the source of the extracellular matrix in animal cells and what are the 3 functions ?
The extracellular matrix is formed by a secretion of glycoproteins from the cell.
1. support
2. adhesion
3. movement
55
Define the term "against concentration gradient"
Moves substances from an area where it is in lower concentration to an area where it is in higher concentration.
56
What are the main features of the phospholipid tail ?
1. Non polar
2. Hydrophobic
3. Located inside the membrane
57
How do Hydrophobic and Hydrophilic properties of Phospholipids help maintain the structure of the membrane ?
1. Hydrophobic fatty acids tails repel water and form the middle layer of the membrane.
2. Hydrophilic phosphate heads attract water and form the outer layers of the membrane.
58
Define "concentration gradient"
Molecules can diffuse across membranes from areas of higher to lower concentration by : simple or facilitated diffusion.
59
State the 15 parts of a Eukaryotic cell
1. Nucleus
2. Microtubule
3. Mitochondrion
4. Rough endoplasmic reticulum (RER)
5. Lysosome
6. Microfilaments
7. Vacuole
8. Ribosomes
9. Golgi complex
10. Cell membrane
11. Centrosomes
12. Smooth endoplasmic reticulum (SER)
13. Nucleolus
14. Centriole
15. Vesicle
60
State the 6 main functions of the cytoplasm
1. Fluid filling the space inside the plasma membrane
2. Water with many dissolved substances
3. contains many enzymes
4. contains ribosomes
5. does NOT contain any membrane bound organelles
6. carries out the chemical reactions of metabolism
61
Give 2 examples of prokaryotic cells
Bacteria for ex. E.Coli
| Cyanobacteria for ex. Blue and Green Algae
62
What are the 2 main functions of free ribosomes ?
1. Site for protein synthesis for use within the cytoplasm.
| 2. Ribosomes are constructed in the nuclear region called nucleolus.
63
What are the 7 main facts about Eukaryotic cells ?
1. DNA associated with proteins
2. True nucleus (enclosed by nuclear membrane)
3. Many membrane bound organelles to compartmentalise functions (golgi, Er,...)
4. Ribosome size + 80 S
5. All cells other than bacteria
6. Size = 2-1000um
7. evolved 1.5-2 billion years ago
64
What are the 5 main functions of plasma membrane ?
1. ) thin layer mainly composed of phospholipids pushed up against the inside of the cell wall.
2. ) Provides selectively permeable barrier between homeostatically controlled interior and fluctuating exterior environments.
3. ) Controls entry and exit of substances
4. ) Can produce ATP by cell respiration
5. Can also pump substances in and out by active transport
65
State the 4 main functions of the flagella
1. ) structures protruding from cell wall with a corkscrew shape
2. ) base is embedded in the cell wall.
3. ) Using energy, they can be rotated to propel the cell from an area to another.
4. ) Unlike eukaryotic flagella, they are solid and inflexible, working like a propeller.
66
State 3 main functions of Lysosomes
1. spherical vesicles formed by Golgi apparatus
2. Contain hydrolytic/ digestive enzymes
3. Enzymes for breaking down ingested food, damaged organelles or entire cells.
67
What 5 functions does the cell wall have in a prokaryote ?
1. ) It is always present
2. ) It is composed of Peptidoglycan
3. ) it provides physical protection
4. ) It maintains cell shape
5. ) prevents bursting in hypotonic environments
68
What are the 3 main functions of Mitochondria ?
1. Double membrane bound
2. inner membrane invaginated to form cristae
3. site of aerobic respiration, producing ATP
69
State the 4 main functions of the nucleoid
1. region of the cytoplasm containing the genetic material (1molecule of DNA)
2. DNA is circular and naked (not associated with protein)
3. Total amount of DNA is much smaller than in Eukaryotes
4. the nucleoid is stained less densely than the rest of the cytoplasm because there are fewer ribosomes.
70
State the 4 main functions of the pili
1. ) Protein filaments protruding from the cell wall.
2. ) can be pulled in or push out by ratchet mechanism (laptop)
3. ) used when bacteria stick together to form aggregations of cells
4. ) Used when two cells are exchanging DNA during conjugation.
71
What is the definition of a Eukaryotic cell ?
A eukaryote is an organism whose cells contain a nucleus and other structures enclosed within membranes.
72
State the 3 main functions of the ribosomes
1. small granular structure (70S)
2. smaller than eukaryotic ribosomes wich are 80S
3. site for protein synthesis
73
State 4 main functions of the nucleus
1. Double membrane bound, containing pores for transport of proteins and ribosomes
2. contains chromosomes, made of DNA + proteins
3. uncoiled chromosomes + chromatin
4. Site of DNA replication and transcription into RNA
74
How do prokaryotic cells divide ?
By binary fission
75
What are the 7 main facts about Prokaryotic cells ?
1. Naked DNA
2. DNA in cytoplasm (no nuclear membrane)
3. No membrane bound organelles (no mitochondria,golgi...)
4. Ribosome size + 70 S
5. Only bacteria
6. Size = 1-10 um
7. evolved at least 3.5 billion years ago
76
What is the definition of a Prokaryotic cell ?
The prokaryotes are a group of organisms whose cells lack a membrane-bound nucleus.
77
State 5 main functions of Golgi apparatus
1. consists of flattened membrane sacs called cisternae
2. unlike ER, cisternae are curved shorter and lack ribosomes
3. Proteins received from arriving vesicles are processed
4. Carbohydrate added to proteins to form glycoproteins.
5. Vesicles of glycoproteins exit Golgi for exocytosis or intracellular use.
78
What is an organ ?
An organ is a centre of body function specialised for that one function that is composed of several different types of tissue
79
State the advantages of Light Microscope
1. ) colour images instead of monochromic
2. ) easily prepared sample material
3. ) possibility to observe living material and movement
4. ) larger field of view
80
For how many functions is each cell specialised ?
Only one.
| Ex. Nerve cells transmit messages
81
Explain nutrition
Obtaining Food to provide energy and all the material needed for growth
82
What are the ethical issues of embryonic stem cells?
Using embryonic stem cells involves the death of an early stage embryos.
83
State the 6 functions of life carried by unicellular organisms :
```
Metabolism
Sensitivity
Homeostasis
Growth
Reproduction
Nutrition
```
84
State the advantages of Electron Microscopes
1. ) higher resolution
2. ) more separate particles and clearer picture
3. ) Higher magnification to see smaller objects
85
Do cells have the possibility to carry any specialisation ?
Yes. They could develop into any way but the genes are not turned on.
86
What is surface area to volume ratio in a cell ?
Surface area to volume ratio decreases when VOLUME INCREASES.
Larger the object = smaller the surface area to volume ratio = slower diffusion rate
87
What do cells contain ?
Nucleus (chromosomes--->DNA----> Genes)
88
Outline 4 points on "origin of life"
1. ) life always existed is incompatible with geological evidence on age of earth
2. ) exception made for origin of life, cells must have arisen from non living substances
3. ) condition of early earth are Anaerobic = precluding the formation of cells from non-living substances
89
```
State the sizes of the following :
Molecules
Cell membrane
Viruses
Bacteria
Organelles
Eukaryotic cells
```
```
Molecules : ~1nm
Cell membrane : ~ 10nm
Viruses : ~ 100nm
Bacteria :~ 1um
Organelles : up to 10um
Eukaryotic cells : up to 100um
```
90
Why do cells in multicellular organism differentiate ?
To become specialised !
91
Name 4 blood disorders than can be cured by HS cells
1. ) Acute leukemia
2. ) SCID (severe combined immune deficiency)
3. ) Multiple myeloma
4. ) lymphoma
92
Explain homeostasis
Keeping conditions inside the organisms within tolerable limits
93
What do groups of differentiated cells form ?
A tissue
94
Explain the 5 steps of lymphoma
1. ) cells are removed from the bone marrow of the patient
2. ) High doses of chemotherapy are taken by the patient to kill dividing cells in the body
3. ) Both cancerous and normal cells are killed
4. ) HS cells from the bone marrow are then transplanted back into the patient
5. ) These HS cells then fully restore healthy production of blood cells in the bone marrow.
95
What is cellular differentiation ?
The development of cells in specific ways
| Ex. Hormones, cell to cell signals, and chemicals determines how a cell develops
96
What does "um" and "nm "mean ?
| And what are their sizes in relation to each other ?
```
"nm" = nanometer
"um" = micrometer
```
```
1000nm = 1um
1000um = 1mm
```
97
A theory can be : ... Or ....
Rejected or adapted
98
What are the ethical issues regarding therapeutic cloning ?
Therapeutic cloning could reduce suffering for the patients with wide variety of conditions.
99
State 1 characteristic of a unicellular organism :
Must solve all of life's challenges within the confines of a single cell
100
What is a tissue ?
A tissue is an integrated group of cells that have a common structure and function
101
What is an organ system ?
An organ system is a group of organs that specialise in a certain function together
102
As evidence is accumulated theories need to be :
Reviewed or altered or abandoned
103
What makes a hypothesis become a theory ?
Accumulation if evidence
104
What organisms are considered acellular ?
Unicellular organisms
| Viruses
105
What is the size of most plant and animal cells ?
Between 100um to 10 um
106
Outline the 4 therapeutic use of stem cells
1. ) Bone marrow transplants use hematopoietic stem cells(HScells)
2. ) HS cells are found in bone marrow and divide continually (producing red and white blood cells)
3. ) Just 100 HS cells can replace the blood system of mice when bone marrow is destroyed by radiation
4. ) HS cells are used in the treatment of numerous blood disorders.
107
What do stem cells do ?
They retain the capacity to divide and have the ability to differentiate along different pathways.
108
Outline 3 characteristics of the cells :
1. )nothing smaller than a cell can survive independently
2. ) sub cellular structures cannot live independently (nuclei, Golgi, chloroplast...)
3. ) the lower limit on cell size is about 200nm
109
Explain growth
An irreversible increase in size
110
State 4 characteristics of Multicellular organisms :
1. ) can differentiate into a variety of interdependent cell types
2. ) each specialised to carry out a subset of functions
3. ) thereby achieving a greater efficiency
4. ) through division of labor among a multicellular cooperative
111
```
State the sizes of these :
Atom
Small molecules
Lipids
Proteins
Ribosomes
Mitochondrion
```
```
Atoms = ~0.1 nm
Small molecules =~ less than 1nm
Lipids =~ 1-5 nm
Proteins =~ 5-10 nm
Ribosomes =~ less than 50 nm
Mitochondrion =~ 2um
```
112
Explain Metabolism
Chemical reactions inside the cells , including cell respiration to release energy.
113
Explain sensitivity
Perceiving and responding to changes in the environment
114
Explain reproduction
Producing offspring either sexually or asexually
115
What is the magnification formula ?
Size of image / actual size of specimen
116
What are the 4 outlines of cell theory ?
1. ) living organisms are composed of cells
2. ) Cells are the smallest unit of life
3. ) Cells come from pre-existing cells
4. ) Cells are units if structure and function
117
Define an organelle
An organelle is a discrete structure within a cell that has a specific function, it also needs to be covered by its own membrane.
