Topic 3 Cells Specialization Flashcards
1
Q
What are the two types of cells?
A
Prokaryotic cells and Eukaryotic cells
Prokaryotic cells are typically single-celled organisms, while eukaryotic cells are found in multicellular organisms.
2
Q
What are organelles?
A
Parts of cells, each with a specific function
Organelles are essential for the cell’s operation and can be found in both prokaryotic and eukaryotic cells.
3
Q
What is a key feature of prokaryotic organisms?
A
They are made up of prokaryotic cells
Prokaryotic organisms are typically single-celled.
4
Q
What type of cells are animal cells?
A
Eukaryotic cells
Eukaryotic cells are more complex than prokaryotic cells.
5
Q
What distinguishes eukaryotic cells from prokaryotic cells?
A
Eukaryotic cells are larger and more complex
Eukaryotic cells include all animal and plant cells.
6
Q
Name three organelles found in animal cells.
A
- Nucleus
- Mitochondrion
- Ribosome
These organelles have specific functions vital for cell health and activity.
7
Q
What is the function of the nucleus?
A
Controls cell activities and contains DNA
The nucleus is surrounded by a double membrane called the nuclear envelope.
8
Q
What is the role of ribosomes?
A
Site where proteins are made
Ribosomes can be free in the cytoplasm or attached to the rough endoplasmic reticulum.
9
Q
Fill in the blank: The _______ contains digestive enzymes.
A
Lysosome
Lysosomes digest invading cells or worn-out components of the cell.
10
Q
What is the function of the mitochondrion?
A
Site of aerobic respiration where ATP is produced
Mitochondria are abundant in cells that require a lot of energy.
11
Q
True or False: Organelles are whole cells.
A
False
Organelles are parts of cells, not complete cells.
12
Q
What are the components of the rough endoplasmic reticulum (RER)?
A
Covered with ribosomes and involved in protein folding and processing
The RER synthesizes proteins that are to be exported from the cell.
13
Q
What is the function of the Golgi apparatus?
A
Processes and packages lipids and proteins
The Golgi apparatus also makes lysosomes.
14
Q
Fill in the blank: The _______ is involved with the separation of chromosomes during cell division.
A
Centriole
Centrioles are found in animal cells and some plant cells.
15
Q
What is the structure of the mitochondrion?
A
Double membrane with inner folds called cristae
The matrix inside contains enzymes for respiration.
16
Q
What is the function of smooth endoplasmic reticulum (SER)?
A
Synthesizes and processes lipids
The SER is involved in the production of hormones and other lipids.
17
Q
Where are proteins made in a cell?
A
At the ribosomes
Ribosomes can be found on the rough endoplasmic reticulum or free in the cytoplasm.
18
Q
What do ribosomes on the rough endoplasmic reticulum produce?
A
Proteins that are excreted or attached to the cell membrane
19
Q
What is the role of free ribosomes in the cytoplasm?
A
Make proteins that stay in the cytoplasm
20
Q
What happens to new proteins in the rough endoplasmic reticulum?
A
They are folded and processed
21
Q
How are proteins transported from the rough endoplasmic reticulum?
A
In vesicles to the Golgi apparatus
22
Q
What further processing can occur at the Golgi apparatus?
A
Sugar chains are trimmed or more are added
23
Q
What do proteins enter after the Golgi apparatus for transport?
A
More vesicles
24
Q
What is an example of a protein that moves to the cell surface?
A
Extracellular enzymes (like digestive enzymes)
25
How do prokaryotic cells compare in size to eukaryotic cells?
Prokaryotic cells are smaller
26
What is the main component of the plasma membrane in prokaryotic cells?
Lipids and proteins
27
What is the function of the cell wall in prokaryotic cells?
Supports the cell and prevents it from changing shape
28
What is murein?
A polymer that makes up the cell wall in prokaryotic cells
29
What type of ribosomes are found in prokaryotic cells?
Smaller ribosomes than those in eukaryotic cells
30
What are pili in prokaryotic cells?
Short hair-like structures that help stick to other cells
31
What is the function of a flagellum?
Rotates to make the prokaryotic cell move
32
True or False: All prokaryotes have a flagellum.
False
33
What is a capsule in prokaryotic cells?
A structure made of secreted slime that protects bacteria
34
What distinguishes the DNA in prokaryotic cells from that in eukaryotic cells?
It floats free in the cytoplasm and is circular
35
What are plasmids?
Small loops of DNA that aren't part of the main circular DNA molecule
36
What genes do plasmids typically contain?
Genes for antibiotic resistance
37
Fill in the blank: Prokaryotic cells do not have a _______.
Nucleus
38
What are mesosomes?
Inward folds in the plasma membrane of prokaryotic cells
39
What is debated about the function of mesosomes?
Whether they play a role in cellular processes or are artefacts
40
Identify one structure that can only be found in prokaryotic cells.
Pili
41
Describe two ways in which DNA can be stored in a prokaryotic cell.
1. Circular DNA as one long coiled-up strand. 2. Plasmids (small loops of DNA).
42
What is magnification?
Magnification is how much bigger the image is than the specimen.
## Footnote
It is calculated using the formula: size of image / size of real object.
43
What is the formula for calculating magnification?
Magnification = size of image / size of real object.
44
What is resolution in microscopy?
Resolution is how detailed the image is and how well a microscope distinguishes between two points that are close together.
45
What is an eyepiece graticule?
An eyepiece graticule is a transparent ruler fitted onto the eyepiece of a microscope, used to measure the size of a specimen.
46
What is a stage micrometer?
A stage micrometer is a microscope slide with an accurate scale used to measure the size of an object in micrometers.
47
What are the two main types of microscopes?
* Light microscopes
* Electron microscopes
48
What is the maximum resolution of light microscopes?
The maximum resolution of light microscopes is about 0.2 micrometres (um).
49
What is the maximum useful magnification of a light microscope?
The maximum useful magnification of a light microscope is about × 1500.
50
What is the maximum useful magnification of an electron microscope?
The maximum useful magnification of an electron microscope is about × 1,500,000.
51
What is the difference between transmission electron microscopes (TEMs) and scanning electron microscopes (SEMs)?
* TEMs use electromagnets to focus a beam of electrons transmitted through the specimen.
* SEMs scan a beam of electrons across the specimen, showing surface details.
52
What are the advantages of TEMs?
* High resolution images
* Can show internal structure of organelles
53
What are the disadvantages of TEMs?
TEMs can only be used on thin specimens.
54
What are the advantages of SEMs?
* Can be used on thick specimens
* Produce 3D images
55
What are the disadvantages of SEMs?
SEMs give lower resolution images than TEMs.
56
How do you convert micrometers (um) to millimeters (mm)?
To convert micrometers to millimeters, divide by 1000.
57
What is the maximum resolution of electron microscopes?
The maximum resolution of electron microscopes is about 0.0002 micrometres (um).
58
True or False: A light microscope can view organelles smaller than 0.2 um.
False.
59
How are the images produced by SEMs different from those produced by TEMs?
SEMs show surface details and can be 3D, while TEMs provide high resolution internal images.
60
What is the significance of calibrating the eyepiece graticule?
The eyepiece graticule needs to be re-calibrated at different magnifications.
61
What is squamous epithelium?
A single layer of flat cells lining a surface, found in places like the alveoli in the lungs.
62
What is ciliated epithelium?
A layer of cells with tiny hair-like structures (cilia) that move substances, found in the trachea.
63
What is the function of the basement membrane?
It supports the epithelium tissue by anchoring it to underlying tissues.
64
What are the two primary functions of xylem tissue?
* Transporting water around the plant
* Supporting the plant.
65
What types of cells are found in xylem tissue?
* Xylem vessel cells
* Xylem parenchyma cells.
66
What is cartilage?
A type of connective tissue found in joints, ears, nose, and windpipe.
67
What is an organ?
A group of different tissues that work together to perform a particular function.
68
Name the tissues that make up a plant leaf.
* Lower epidermis
* Spongy mesophyll
* Palisade mesophyll
* Xylem
* Phloem
* Upper epidermis.
69
What is the role of stomata in the lower epidermis of a leaf?
To allow air in and out for gas exchange.
70
Where does most photosynthesis occur in a leaf?
In the palisade mesophyll.
71
What tissues make up the lungs?
* Squamous epithelium tissue
* Fibrous connective tissue
* Endothelium tissue.
72
What is the respiratory system?
A system made up of all organs, tissues, and cells involved in breathing.
73
Name the organs involved in the respiratory system.
* Lungs
* Trachea
* Larynx
* Nose
* Mouth
* Diaphragm.
74
What is the circulatory system?
A system made up of the organs involved in blood supply.
75
Name the parts of the circulatory system.
* Heart
* Arteries
* Veins
* Capillaries.
76
Fill in the blank: Tissues are organized into _______.
Organs.
77
True or False: Xylem tissue is made up of a group of organs that work together.
False.
78
True or False: The lungs are part of the respiratory system.
True.
79
Explain what is meant by the term organ system.
A group of organs working together to perform a particular function.
80
Name one organ found in plants and one organ found in animals.
* Plant organ: Leaf
* Animal organ: Lungs.
81
What is mitosis?
Mitosis is cell division that produces genetically identical daughter cells.
## Footnote
Mitosis is crucial for growth, repair, and asexual reproduction.
82
What happens to a parent cell during mitosis?
A parent cell divides to produce two genetically identical daughter cells.
83
What is the purpose of mitosis in multicellular organisms?
Mitosis is used for growth, repair, and asexual reproduction.
84
What is interphase?
Interphase is the period of cell growth and DNA replication before mitosis.
85
What are the three stages of interphase?
G1, S, and G2.
86
What occurs during the S phase of interphase?
The cell replicates its DNA in preparation for division.
87
What are the four stages of mitosis?
Prophase, Metaphase, Anaphase, and Telophase.
88
What happens during prophase?
Chromosomes condense, centrioles move to opposite ends, and the nuclear envelope breaks down.
89
What is the role of the spindle during mitosis?
The spindle helps separate the chromatids during mitosis.
90
What occurs during metaphase?
Chromosomes line up along the middle of the cell and attach to the spindle by their centromeres.
91
What happens during anaphase?
Centromeres divide, separating sister chromatids, which are pulled to opposite poles.
92
What is telophase?
Chromatids reach opposite poles, uncoil, and a nuclear envelope forms around each group, resulting in two nuclei.
93
What is cytokinesis?
Cytokinesis is the division of the cytoplasm, resulting in two daughter cells.
94
Fill in the blank: The mitotic index is calculated using the formula: mitotic index = _______.
number of cells with visible chromosomes / total number of cells observed.
95
Why is it important to squash the tissue when preparing a slide of plant root tip cells?
Squashing the tissue makes it thinner, allowing light to pass through for better observation under a microscope.
96
What is the significance of a high mitotic index in plant root tips?
A high mitotic index indicates rapid tissue growth, as many cells are undergoing mitosis.
97
True or False: All cells in multicellular organisms retain the ability to divide.
False.
98
What increases in the cell during interphase to provide energy for cell division?
ATP content.
99
What are chromatids?
The separate strands of a chromosome, joined at the centromere.
100
What is the function of centrioles during mitosis?
Centrioles help form the spindle apparatus that separates chromatids.
101
What is the role of the nuclear envelope during mitosis?
The nuclear envelope breaks down during prophase and reforms during telophase.
102
What is the appearance of chromosomes during anaphase?
Chromatids appear V-shaped as they are pulled to opposite poles.
103
What are the male and female gametes in animals?
Male gametes are sperm and female gametes are egg cells (ova).
104
How many chromosomes do normal body cells contain in humans?
46 chromosomes.
105
How many chromosomes do gametes contain?
Gametes contain 23 chromosomes.
106
What is fertilisation?
The moment when the nuclei of the male and female gametes fuse.
107
What is the result of fertilisation?
A zygote with the full number of chromosomes.
108
What makes offspring genetically unique?
Combining genetic material from two individuals.
109
Fill in the blank: In mammals, fertilisation occurs in the _______.
oviduct.
110
What is the zona pellucida?
A protective glycoprotein layer that sperm have to penetrate.
111
What happens during the acrosome reaction?
Digestive enzymes are released from the acrosome of the sperm.
112
What is the function of the acrosome in sperm?
Contains digestive enzymes to break down the egg cell's zona pellucida.
113
What triggers the cortical reaction in the egg cell?
The fusion of the sperm head with the cell membrane of the egg cell.
114
What happens to the zona pellucida after the cortical reaction?
It thickens and becomes impenetrable to other sperm.
115
What occurs immediately after a zygote is formed?
It begins to divide by mitosis.
116
True or False: Egg cells are smaller than sperm cells.
False.
117
List two specialisations of sperm cells.
* Flagellum for swimming
* Lots of mitochondria for energy.
118
List two specialisations of egg cells.
* Larger size compared to sperm
* Contains food reserves for the developing embryo.
119
What is the role of mitochondria in sperm cells?
Releases energy in the form of ATP for swimming.
120
What process produces gametes?
Meiosis
## Footnote
Meiosis is a type of cell division that reduces the chromosome number by half, producing gametes.
121
How many chromosomes do cells that undergo meiosis have at the start?
Full set of chromosomes
## Footnote
Cells that divide by meiosis start with a full set of chromosomes.
122
What is the chromosome number in cells formed from meiosis?
Half the number of chromosomes
## Footnote
The resulting cells from meiosis have half the chromosome number to maintain genetic stability during fertilization.
123
What happens to chromosome number during the first division of meiosis?
Halved
## Footnote
The first division separates homologous pairs, halving the chromosome number.
124
What is genetic variation?
Differences in individuals' genetic material
## Footnote
Genetic variation is crucial for evolution and adaptation.
125
What are the two main mechanisms by which meiosis creates genetic variation?
* Crossing over of chromatids
* Independent assortment of chromosomes
126
What occurs during crossing over?
Chromatids twist and exchange genetic material
## Footnote
This recombination creates different combinations of alleles.
127
What is independent assortment?
Random distribution of maternal and paternal chromosomes
## Footnote
This process ensures that gametes have different combinations of chromosomes.
128
What is a locus?
The position of a gene on a chromosome
## Footnote
Loci are important for understanding gene linkage and inheritance.
129
What does it mean when genes are linked?
They are located on the same chromosome and tend to be inherited together
## Footnote
Linked genes are less likely to be separated during meiosis unless crossing over occurs.
130
What is a sex-linked characteristic?
A characteristic coded by an allele on a sex chromosome
## Footnote
Most sex-linked characteristics are found on the X chromosome.
131
What are X-linked disorders?
Genetic disorders caused by faulty alleles on the X chromosome
## Footnote
Examples include color blindness and hemophilia.
132
True or False: Males have two X chromosomes.
False
## Footnote
Males have one X and one Y chromosome, while females have two X chromosomes.
133
Fill in the blank: The Y chromosome is ______ than the X chromosome.
smaller
134
Why are males more likely to express recessive phenotypes for sex-linked genes?
They have only one allele for sex-linked genes
## Footnote
Because males have one X chromosome, they express the characteristic even if it's recessive.
135
What is produced at the end of meiosis?
Four genetically different gametes
## Footnote
Each gamete has a unique combination of alleles.
136
What are stem cells?
Unspecialised cells that can develop into other types of cells.
## Footnote
Stem cells can differentiate into specialized cells through a process called differentiation.
137
What is the process by which a cell becomes specialised?
Differentiation.
138
What are the two types of potency in stem cells?
* Totipotency
* Pluripotency
139
What does totipotency refer to?
The ability to produce all cell types, including extraembryonic cells.
140
What does pluripotency refer to?
The ability of a stem cell to produce all specialized cells in an organism, excluding extraembryonic cells.
141
When are totipotent stem cells present in mammals?
During the first few cell divisions of an embryo.
142
Where are adult stem cells found?
In some adult tissues, such as the intestines.
143
What determines the specialization of a cell?
Differential gene expression.
144
What is transcription?
The process of copying DNA into mRNA.
145
What is translation?
The process of producing proteins using the code in mRNA.
146
What are transcription factors?
Proteins that bind to DNA and regulate gene expression.
147
What is the role of activators in gene expression?
They increase the rate of transcription.
148
What is the role of repressors in gene expression?
They decrease the rate of transcription.
149
What is an operon?
A section of DNA that contains a cluster of structural genes and control elements.
150
What is the lac operon?
An operon in E. coli that produces enzymes needed to respire lactose.
151
What happens to the lac operon when lactose is present?
Lactose binds to the lac repressor, allowing transcription of the structural genes.
152
Fill in the blank: The ability of stem cells to differentiate into specialised cells is called _______.
potency.
153
True or False: All stem cells can differentiate into any type of cell.
False.
154
What are the structural genes on the lac operon responsible for?
Producing proteins that help the bacteria digest lactose.
155
What happens to embryonic stem cells after early development?
They become pluripotent and lose the ability to become extraembryonic cells.
156
What is the significance of differential gene expression in stem cells?
It results in the activation of specific genes that lead to specialization.
157
What occurs when RNA polymerase binds to the promoter in transcription?
It initiates the transcription of structural genes.
158
What does the regulatory gene in an operon do?
Codes for an activator or repressor.
159
What are stem cells?
Cells that can develop into any specialized cell type.
160
Name a disease that stem cell therapy can potentially treat.
Leukemia.
161
What type of stem cells are found in adult tissue?
Adult stem cells.
162
What type of stem cells are obtained from early embryos?
Embryonic stem cells.
163
List three conditions that scientists are researching stem cells to treat.
* Spinal cord injuries
* Heart disease
* Damage caused by heart attacks
164
Fill in the blank: Stem cells could be used to _______ damaged tissues in a range of diseases.
replace
165
What is a potential benefit of stem cell therapies?
They could save many lives.
166
True or False: Adult stem cells can develop into all types of specialized cells.
False.
167
What procedure is used to create embryos for obtaining embryonic stem cells?
In vitro fertilization (IVF).
168
What is the risk associated with using a patient's own adult stem cells for a transplant?
Less risk of rejection.
169
What ethical issue is raised by obtaining stem cells from embryos?
Destruction of a viable embryo.
170
Some people believe that a genetically unique individual is formed at _______.
the moment of fertilization.
171
What is one reason some people oppose using embryonic stem cells?
It destroys embryos.
172
Name a benefit of using embryonic stem cells over adult stem cells.
They can develop into all types of specialized cells.
173
List two ways regulatory authorities help manage stem cell research.
* Licensing and monitoring research centers
* Producing guidelines and codes of practice
174
Fill in the blank: Regulatory authorities ensure that research involving embryos is carried out for a _______.
good reason.
175
True or False: Adult stem cells are more flexible than embryonic stem cells.
False.
176
What do regulatory authorities monitor in scientific research?
Developments and advances in the field.
177
What is one potential application of stem cells for blind individuals?
Replace damaged cells in the eyes.
178
What is one challenge that scientists face in stem cell research?
Ethical issues surrounding embryonic stem cells.
179
Explain one reason why some people support using stem cells from unfertilized egg cells.
They can't survive past a few days and wouldn't produce a fetus.
180
What is continuous variation?
Continuous variation is when individuals in a population vary within a range, with no distinct categories. Examples include height and skin color.
181
What is discontinuous variation?
Discontinuous variation is when individuals fall into distinct categories, such as blood groups.
182
Give an example of a characteristic that shows discontinuous variation.
Blood group
183
What type of variation do most characteristics exhibit?
Polygenic variation
184
What is a monogenic characteristic?
A characteristic controlled by only one gene, showing discontinuous variation.
185
What is the significance of alleles in genotype variation?
Different genotypes arise from different combinations of alleles.
186
How does genotype influence phenotype?
Variation in genotype results in variation in phenotype, the characteristics displayed by an organism.
187
True or False: Some characteristics are influenced only by genotype.
True
188
What environmental factor is known to affect height?
Nutrition
189
How can cancer risk be influenced?
Cancer risk can be influenced by both genetic factors and environmental factors such as diet.
190
What is methylation of DNA?
Methylation is the attachment of a methyl group to DNA, which can repress gene expression.
191
What are histones?
Histones are proteins that DNA wraps around to form chromatin.
192
What effect does histone acetylation have on chromatin?
Histone acetylation makes chromatin less condensed, allowing transcription proteins to bind and activate genes.
193
Fill in the blank: Increased methylation of DNA ______ a gene.
represses
194
What happens to epigenetic changes during cell division?
Epigenetic changes may be passed on to daughter cells.
195
What is the role of environmental changes in gene expression?
Environmental changes can alter gene expression through mechanisms like epigenetic modifications.
196
Give an example of a polygenic characteristic.
Height
197
What are CpG sites in the context of DNA methylation?
CpG sites are where a methyl group attaches to DNA, specifically where cytosine and guanine bases are adjacent.
