Cell biology Flashcards
1
Q
What are the main organelles in an animal cell?
A
Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes.
2
Q
What additional organelles do plant cells have that animal cells do not?
A
Cell wall, chloroplasts, permanent vacuole.
3
Q
What is the function of the nucleus?
A
It contains genetic material (DNA) and controls the cell’s activities.
4
Q
What does the cytoplasm do?
A
it is a gel-like substance where chemical reactions take place, controlled by enzymes.
5
Q
What is the role of the mitochondria?
A
It is the site of aerobic respiration, providing energy for the cell.
6
Q
What are ribosomes responsible for?
A
Protien synthsis
7
Q
What does the cell membrane do?
A
It controls what enters and leaves the cell.
8
Q
What is the function of the cell wall in plant cells?
A
It provides structure and support, made of cellulose.
9
Q
Why do plant cells have chloroplasts?
A
They contain chlorophyll for photosynthesis to make food (glucose).
10
Q
What is the role of the permanent vacuole?
A
To support the cell and store sap
11
Q
How do prokaryotic cells differ from eukaryotic cells?
A
Prokaryotic cells (e.g., bacteria) have no nucleus; their DNA is in a single loop and may have plasmids.
12
Q
What structures do bacterial cells have?
A
Cell wall, cell membrane, cytoplasm, single loop of DNA, plasmids, ribosomes, flagella (sometimes).
13
Q
What is mitosis?
A
A type of cell division that produces two genetically identical daughter cells
14
Q
Why is mitosis important?
A
It allows for growth, repair, and asexual reproduction
15
Q
What are the stages of the cell cycle?
A
Interphase(Sub-cellular stuctures duplication and genetic material) , Mitosis, Cytokinesis
16
Q
What happens during interphase?
A
The cell grows, DNA is replicated, and organelles are made (takes up 90% of a cells life)
17
Q
What are the four stages of mitosis?
A
Prophase, Metaphase, Anaphase, Telophase (PMAT)
18
Q
What happens in prophase?
A
Chromosomes condense and become visible
Nuclear membrane breaks down
Spindle fibers begin to form
19
Q
What happens in metaphase?
A
Chromosomes line up in the center of the cell
Spindle fibers attach to centromeres
20
Q
What happens in anaphase?
A
Spindle fibers pull sister chromatids apart to opposite sides of the cell
21
Q
What happens in telophase?
A
Chromosomes uncoil
New nuclear membranes form around each set of chromosomes
22
Q
What is cytokinesis?
A
The cytoplasm divides, forming two separate daughter cells
23
Q
How many daughter cells are produced in mitosis?
A
Two
24
Q
How do the daughter cells compare to the parent cell?
A
They are genetically identical to the parent cell
25
What type of cells undergo mitosis?
Body (somatic) cells
26
how does mitosis differ from meiosis?
Mitosis produces 2 identical cells, while meiosis produces 4 genetically different cells
Mitosis is for growth/repair, meiosis is for sexual reproduction
27
What is uncontrolled mitosis?
When cells divide uncontrollably, leading to cancer
28
What is binary fission?
Binary fission is a method of asexual reproduction in which a single organism divides into two identical daughter cells.
29
Which organisms commonly use binary fission?
Prokaryotic organisms, such as bacteria, commonly reproduce by binary fission.
30
How does binary fission work?
The DNA of the parent cell is replicated.
The cell elongates, and the two copies of DNA move to opposite ends.
The cell membrane pinches in the middle.
The cell divides into two identical daughter cells.
31
How does binary fission differ from mitosis?
Binary fission occurs in prokaryotes (e.g., bacteria) and is simpler, while mitosis occurs in eukaryotes and involves more complex stages.
32
How long does binary fission take?
The process can take as little as 20 minutes, depending on the conditions (e.g., temperature, nutrients)
33
What is the result of binary fission?
Two genetically identical daughter cells are produced.
34
Why is binary fission an important process for bacteria?
It allows bacteria to reproduce quickly and form large populations under favorable conditions.
35
What are stem cells?
Stem cells are undifferentiated cells that have the ability to develop into different types of specialized cells.
36
What are the two main types of stem cells?
Embryonic stem cells - Found in early embryos; can differentiate into any type of cell.
Adult stem cells - Found in adult tissues; can differentiate into a limited range of cell types.
37
What is the difference between embryonic stem cells and adult stem cells?
Embryonic stem cells are pluripotent (can form any type of cell).
Adult stem cells are multipotent (can only form certain types of cells related to the tissue they are found in).
38
What is differentiation?
Differentiation is the process by which stem cells become specialized to perform specific functions in the body.
39
What are the uses of stem cells in medicine?
Treating diseases like leukemia (bone marrow stem cells).
Regenerating damaged tissues (e.g., spinal cord injuries).
Potential for organ regeneration and treatment of conditions like Parkinson's disease.
40
Q: What are the ethical concerns surrounding the use of embryonic stem cells?
Destruction of embryos during the process.
Moral and religious concerns about the rights of embryos.
41
here can stem cells be found in the human body?
Embryonic stem cells are found in early embryos.
Adult stem cells are found in tissues like bone marrow, skin, and the brain.
42
What is therapeutic cloning?
Therapeutic cloning involves creating a clone of an organism’s cells to harvest stem cells for medical treatment without rejecting them.
43
What is the potential of stem cells in research?
Stem cells can help scientists understand how cells develop, leading to new treatments and advances in regenerative medicine.
44
What is a "totipotent" stem cell?
A totipotent stem cell has the potential to differentiate into any type of cell in the body, including extra-embryonic cells (like the placenta). This is only found in the early stages of an embryo.
45
What is differentiation?
Differentiation is the process by which a stem cell becomes specialized to perform a specific function in the body.
46
What is a specialized cell?
A specialized cell is a cell that has developed specific features to perform a particular function.
47
Why do cells become specialized?
Cells become specialized to perform specific tasks more efficiently, ensuring the body functions properly.
48
What is the role of red blood cells?
Red blood cells carry oxygen around the body. They are specialized with a biconcave shape to increase surface area for oxygen absorption, and they have no nucleus to maximize space for hemoglobin.
49
What is the role of nerve cells (neurons)?
Nerve cells transmit electrical impulses around the body. They are long and have branched connections to form networks, which allow communication between different parts of the body.
50
What is the role of muscle cells?
Muscle cells contract and relax to allow movement. They contain many mitochondria to supply energy for contraction and are long to allow them to stretch and contract.
51
What is the role of sperm cells?
Sperm cells are specialized for reproduction. They have a tail (flagellum) to swim to the egg, and a large nucleus that contains genetic information.
52
What is the role of root hair cells?
Root hair cells are specialized for the absorption of water and minerals from the soil. They have long extensions (root hairs) to increase surface area for absorption.
53
What is the role of xylem cells?
Xylem cells transport water and minerals from the roots to the rest of the plant. They have thickened walls with lignin to strengthen the tissue and prevent collapsing under pressure.
54
What is the role of phloem cells?
Phloem cells transport sugars and nutrients from the leaves to other parts of the plant. They have sieve plates that allow the flow of substances between cells.
55
How does differentiation affect the appearance of a cell?
Differentiated cells change shape, size, and internal structure to perform their specific functions effectively.
56
What is the relationship between stem cells and differentiation?
Stem cells can differentiate into various specialized cells. As they divide, they become specialized for different functions in the body, such as muscle cells, nerve cells, or red blood cells.
57
Are all cells in the body specialized?
No, not all cells are specialized. Stem cells, for example, are undifferentiated and have the potential to become specialized in different ways.
58
What happens when a cell differentiates?
When a cell differentiates, it develops specific structures and functions that are unique to its role, such as the loss of the ability to divide and the appearance of features like cilia or flagella.
59
What is diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient.
60
What type of particles can diffuse?
Small molecules, such as oxygen, carbon dioxide, and water, can diffuse through cell membranes.
61
Does diffusion require energy?
No, diffusion is a passive process, meaning it does not require energy.
62
Where does diffusion occur?
Diffusion occurs in gases and liquids where particles can move freely. It happens across cell membranes in living organisms.
63
What factors affect the rate of diffusion?
Concentration gradient - A steeper gradient increases the rate.
Temperature - Higher temperatures speed up diffusion.
Surface area - A larger surface area increases the rate.
Distance - The shorter the distance, the faster the diffusion.
64
Why is diffusion important in cells?
Diffusion allows cells to exchange gases (oxygen and carbon dioxide), nutrients, and waste products without using energy.
65
How does oxygen move into cells?
Oxygen diffuses from an area of high concentration (in the lungs) to an area of low concentration (inside the cells).
66
How does carbon dioxide move out of cells?
Carbon dioxide diffuses from an area of high concentration (inside the cells) to an area of low concentration (in the lungs, to be exhaled).
67
What is the concentration gradient?
The difference in concentration of a substance between two areas. A steeper concentration gradient increases the rate of diffusion.
68
How do alveoli in the lungs facilitate diffusion?
Alveoli have a large surface area, thin walls, and a high concentration gradient to allow efficient gas exchange by diffusion.
69
How do root hair cells facilitate the diffusion of water?
Root hair cells have long extensions that increase surface area, allowing more water to diffuse into the cell from the soil.
70
What is osmosis?
Osmosis is a special type of diffusion involving the movement of water across a semi-permeable membrane from an area of low solute concentration to high solute concentration.
71
What is a semi-permeable membrane?
A semi-permeable membrane allows some molecules (like water) to pass through but blocks others (like solute molecules).
72
Does osmosis require energy?
No, osmosis is a passive process, meaning it does not require energy.
73
What is the role of osmosis in cells?
Osmosis helps cells maintain the right balance of water and solutes to ensure they function properly.
74
What happens when a cell is placed in a hypotonic solution?
Hypotonic solution has a lower solute concentration than the cell's interior.
Water moves into the cell, causing it to swell.
If too much water enters, the cell may burst.
75
What happens when a cell is placed in an isotonic solution?
sotonic solution has the same solute concentration as the cell's interior.
Water moves in and out of the cell at the same rate, so the cell remains unchanged.
76
What happens when a cell is placed in a hypertonic solution?
Hypertonic solution has a higher solute concentration than the cell's interior.
Water moves out of the cell, causing the cell to shrink or become flaccid.
77
Why is osmosis important for plant cells?
Osmosis helps maintain turgor pressure in plant cells, which is crucial for keeping the cell rigid and supporting the plant structure.
78
What is turgor pressure?
turgor pressure is the pressure exerted by the cell membrane against the cell wall due to the intake of water through osmosis. It helps the plant maintain its shape.
79
How do osmosis and diffusion differ?
Osmosis specifically refers to the movement of water molecules.
Diffusion is the movement of particles (not just water) from high to low concentration, and it can happen with gases or liquids.
80
What is the effect of osmosis in animal cells?
In a hypotonic solution, animal cells can burst due to excess water intake.
In a hypertonic solution, animal cells shrink as water exits the cell.
81
What is the significance of osmosis in the kidneys?
Osmosis helps regulate the water balance in the body by reabsorbing water from urine back into the blood in the kidneys.
82
What is active transport?
Active transport is the movement of substances across a cell membrane against a concentration gradient (from low to high concentration), requiring energy.
83
Does active transport require energy?
Yes, active transport requires energy in the form of ATP to move substances against the concentration gradient.
84
What is the difference between active transport and diffusion?
Diffusion is passive (no energy required) and moves substances from high to low concentration.
Active transport requires energy and moves substances from low to high concentration.
85
Why is active transport important for cells?
Active transport allows cells to take in substances that are in low concentrations outside the cell, such as nutrients like glucose, or expel waste products.
86
How does active transport work?
A substance binds to a transport protein in the cell membrane.
Energy (from ATP) is used to change the shape of the protein.
The substance is moved against the concentration gradient into the cell (or out of the cell).
87
What is an example of active transport in plants?
In plant roots, mineral ions (such as nitrates) are absorbed from the soil into root cells, even though the concentration of these ions is lower in the soil than inside the plant. This process requires active transport.
88
What is an example of active transport in animals?
In the small intestine, glucose is absorbed into cells from the lumen of the intestine, even when glucose concentration is lower in the intestine than in the cells. This requires active transport.
89
What are carrier proteins?
Carrier proteins are membrane proteins that help move molecules during active transport by changing shape when energy is supplied, allowing substances to pass through the membrane.
90
What is the surface area to volume ratio?
The surface area to volume ratio is the relationship between the surface area of an object and its volume. It shows how much surface area is available for exchanging materials compared to the volume of the object.
91
Why is the surface area to volume ratio important for cells?
A larger surface area to volume ratio allows for more efficient exchange of materials (e.g., gases, nutrients, and waste) across the cell membrane.
92
How does the surface area to volume ratio change as an object gets larger?
As an object (or cell) increases in size, its volume increases faster than its surface area, resulting in a smaller surface area to volume ratio.
93
How does the surface area to volume ratio affect the rate of diffusion?
A higher surface area to volume ratio allows for a faster rate of diffusion, as there is more surface available for substances to move across.
94
How do unicellular organisms deal with surface area to volume ratio issues?
Unicellular organisms have a large surface area to volume ratio, allowing them to exchange materials efficiently through their cell membrane.
95
Why do multicellular organisms need special adaptations for gas exchange?
In multicellular organisms, the surface area to volume ratio is smaller, so they need specialized structures like lungs or gills to increase the surface area for efficient gas exchange.
96
What is an example of an adaptation to increase surface area?
In the small intestine, villi increase surface area, allowing for more efficient absorption of nutrients. Similarly, alveoli in the lungs increase surface area for gas exchange.
97
What is a specialized exchange surface?
The surface area to volume ratio is the relationship between the surface area of an object and its volume. It shows how much surface area is available for exchanging materials compared to the volume of the object.
98
Why is the surface area to volume ratio important for cells?
A larger surface area to volume ratio allows for more efficient exchange of materials (e.g., gases, nutrients, and waste) across the cell membrane.
99
How does the surface area to volume ratio change as an object gets larger?
As an object (or cell) increases in size, its volume increases faster than its surface area, resulting in a smaller surface area to volume ratio.
100
How does the surface area to volume ratio affect the rate of diffusion?
A higher surface area to volume ratio allows for a faster rate of diffusion, as there is more surface available for substances to move across.
101
How do unicellular organisms deal with surface area to volume ratio issues?
Unicellular organisms have a large surface area to volume ratio, allowing them to exchange materials efficiently through their cell membrane.
102
Why do multicellular organisms need special adaptations for gas exchange?
In multicellular organisms, the surface area to volume ratio is smaller, so they need specialized structures like lungs or gills to increase the surface area for efficient gas exchange.
103
