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Biology > topic 1 - cell biology > Flashcards

topic 1 - cell biology Flashcards

1
Q

nucleus

A
  • contains Dna coding for a particular protein needed to build new cells
  • enclosed in a nuclear membrane
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2
Q

Cytoplasm

A
  • Liquid substance in which chemical reactions occur
  • contains enzymes
  • organelles are found in it
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3
Q

Cell membrane

A
  • controls what enters and leaves the cell
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4
Q

Mitochondria

A
  • When aerobic respiration reactions occur, providing energy for the cell
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5
Q

Ribosomes

A
  • where protein synthesis occurs
  • Found on a structure called the rough endoplasmic reticulum
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6
Q

Chloroplasts

A
  • where photosynthesis takes place
  • contains chlorophyll pigment
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7
Q

Permanent vacuole

A
  • contains cell sap
  • found in cytoplasm
  • improves cells rigidity
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8
Q

Cell wall

A
  • made from cellulose
  • provides strength to cell
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9
Q

What process do stem cells undergo to become specialized?

A

Stem cells undergo differentiation to form specialized cells.

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10
Q

What is a characteristic of sperm cells related to their function?

A

Sperm cells are specialized to carry the male’s DNA to the egg cell (ovum) for successful reproduction, and have a streamlined head and long tail to aid swimming.

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11
Q

What adaptation helps nerve cells transmit electrical signals quickly?

A

Nerve cells have a long axon enabling impulses to be carried long distances.

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12
Q

What key feature do muscle cells contain to generate movement?

A

Muscle cells contain special proteins myosin and actin that slide over each other, causing contraction.

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13
Q

What do root hair cells specialize in?

A

Root hair cells specialize in taking up water by osmosis and mineral ions by active transport from the soil. Active transport occurs in the gut when substances such as glucose and amino acids move from the gut into the bloodstream against their concentration gradient.

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14
Q

What is the function of xylem cells in plants?

A

Xylem cells are specialized to transport water and mineral ions up the plant from the roots to the shoots. Active transport occurs in the gut when substances such as glucose and amino acids move from the gut into the bloodstream against their concentration gradient.

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15
Q

Describe the structure and function of phloem cells.

A

Active transport occurs in the gut when substances such as glucose and amino acids move from the gut into the bloodstream against their concentration gradient.

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16
Q

What is the primary component inside the nucleus?

A

The primary component inside the nucleus is chromosomes which contain coils of DNA.

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17
Q

What is a gene?

A

A gene is a short section of DNA that codes for a protein and controls a characteristic.

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18
Q

How many chromosomes are found in human body cells and gametes?

A

There are 46 chromosomes in human body cells (23 pairs), and 23 chromosomes in gametes.

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19
Q

What is interphase in the cell cycle?

A

Interphase is the stage where the cell grows, organelles grow and increase in number, and DNA is replicated.

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20
Q

What are the two types of electron microscopes?

A

The two types of electron microscopes are scanning electron microscope (SEM), which creates 3D images, and transmission electron microscope (TEM), which creates 2D images detailing organelles.

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21
Q

What is the maximum magnification of a light microscope?

A

The maximum magnification of a light microscope is approximately x2000.

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22
Q

What does ‘mean division time’ refer to in the context of bacteria?

A

Mean division time refers to the average time it takes for bacteria to divide, allowing calculation of population size after a given time period.

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23
Q

What is the formula to calculate the number of bacteria after a certain time given mean division time?

A

The formula is: Number of bacteria at the end = (Bacteria at the beginning) x 2^(number of divisions).

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24
Q

Why must Petri dishes and culture media be sterilized before use?

A

They must be sterilized to prevent contamination with other microorganisms that might compete for nutrients or cause harmful effects.

25
What is the process by which bacteria multiply?
Bacteria multiply by binary fission, in which one bacterial cell splits into two.
26
What does standard form allow scientists to do when working with large or small numbers?
Standard form allows scientists to express large or small numbers in a manageable way, using powers of 10.
27
What is the purpose of the antibiotic sensitivity test using paper discs?
It tests the effects of different antibiotics on bacterial growth by measuring the size of the clear area around the discs, known as the inhibition zone.
28
How is the cross-sectional area of a circular structure calculated?
The cross-sectional area is calculated using the formula A = πr², where r is the radius of the circle.
29
What is the role of the inoculating loop during microorganism culturing?
The inoculating loop is used to spread microorganisms evenly over the agar surface.
30
What occurs during the process of DNA replication in mitosis?
DNA is replicated forming the characteristic X shape and energy stores are increased.
31
What happens in Stage 2 of mitosis?
The chromosomes line up at the equator of the cell and cell fibres pull each chromosome of the X to either side of the cell.
32
What is Stage 3 of mitosis called?
Cytokinesis.
33
What results from cytokinesis?
Two identical daughter cells form when the cytoplasm and cell membranes divide.
34
Why is cell division by mitosis important for multicellular organisms?
It is important for their growth and development, and for replacing damaged cells.
35
What type of reproduction involves mitosis?
Asexual reproduction.
36
What is a stem cell?
A stem cell is an undifferentiated cell which can undergo division to produce many more similar cells, some of which will differentiate to have different functions.
37
What are embryonic stem cells?
Embryonic stem cells form when an egg and sperm cell fuse to form a zygote and can differentiate into any type of cell in the body.
38
How can embryonic stem cells be used in medicine?
They could potentially be used to replace insulin-producing cells in those suffering from diabetes, new neural cells for diseases such as Alzheimer's, or nerve cells for those paralyzed with spinal cord injuries.
39
What types of cells can adult stem cells form?
Adult stem cells found in bone marrow can form many types of cells including blood cells.
40
What are meristems in plants?
Meristems are found in root and shoot tips and can differentiate into any type of plant throughout the life of the plant.
41
What is therapeutic cloning?
Therapeutic cloning involves producing an embryo with the same genes as the patient to harvest embryonic stem cells that could be grown into needed tissues or organs.
42
What are some benefits of stem cell research?
They can be used to replace damaged or diseased body parts. Unwanted embryos from fertility clinics could be used as they would otherwise be discarded
43
What are some problems associated with stem cell research?
We do not completely understand the process of differentiation, unwanted embryos may be destroyed, and there are ethical objections. removal of stem cells destroys embryos Religious/ethical objections
44
What is diffusion?
Diffusion is the spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.
45
Is diffusion an active or passive process?
Diffusion is a passive process as no energy is required.
46
What types of molecules can move through cell membranes via diffusion?
Small molecules such as oxygen, glucose, amino acids, and water can move, whereas starch and proteins cannot.
47
Where does gas exchange occur in the body?
Gas exchange occurs in the lungs, particularly across the membranes of structures called alveoli.
48
What affects the rate of diffusion?
Factors affecting the rate of diffusion include concentration gradient, surface area to volume ratio, temperature, and surface area of the membrane.
49
How is surface area to volume ratio calculated?
It is calculated by finding the volume (length x width x height) and the surface area (length x width), and writing the ratio in the smallest whole numbers.
50
Why do single-celled organisms rely on diffusion for transport?
They have a relatively large surface area to volume ratio and low metabolic demands, making diffusion sufficient to meet their needs.
51
What adaptations facilitate gas exchange in fish?
Gills contain gill filaments and gill lamellae, increasing the surface area for diffusion of oxygen into the blood and carbon dioxide into the water.
52
What is osmosis?
Osmosis is the movement of water from a less concentrated solution to a more concentrated one through a partially permeable membrane.
53
What is an isotonic solution in relation to a cell?
An isotonic solution has the same concentration as the internal environment of the cell, resulting in no net movement of water.
54
What happens to an animal cell in a hypertonic solution?
Excess water will leave the cell causing it to become shriveled.
55
What is turgor in plant cells?
Turgor is the pressure resulting from water moving into plant cells and into the vacuole, keeping the leaves and stems rigid.
56
What is active transport?
Active transport is the movement of particles from an area of lower concentration to an area of higher concentration against their concentration gradient, requiring energy.
57
How do root hairs utilize active transport?
Root hairs take up water and mineral ions for healthy growth from the soil, requiring energy when mineral ions are in higher concentrations in the cells.
58
Where does active transport occur in the gut?
Active transport occurs in the gut when substances such as glucose and amino acids move from the gut into the bloodstream against their concentration gradient.

Biology (7 decks)

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