Final Biology 30 Review Flashcards
1
Q
What is DNA analysis used for?
A
is used to study a person’s genetic code, which contains the instructions for how their body works.
2
Q
What Is CRISPR-Cas9, and how does it work?
A
CRISPR:It helps bacteria remember and defend against viruses.
Cas9:A protein that acts like molecular scissors, capable of cutting DNA at specific locations.
How it works:
1. Finding the Target
2.Cutting the DNA
3.Fixing or Changing the DNA:
3
Q
What is gene therapy?
A
Is a medical technique that involves changing or fixing genes in a person’s cells to treat or prevent diseases.
4
Q
What are stem cells, and why are they important in medicine?
A
-Are basic cells that can become almost any type of cell in the body.
-Its important in medicine as it helps with healing and repairing, disease treatment, new discoveries, and regenerative medicine.
5
Q
What is cloning, and how is it done?
A
Making an exact genetic copy of an organism, cell, or DNA molecule.
-It is done by taking the DNA from one organism and inserting it into an egg cell that has its DNA removed. This cell with the donor’s DNA begins to divide and grow into a new organism (a clone).
6
Q
How do vaccines help protect us from diseases?
A
Weakened or dead diseases are injected into the skin and our white blood cells fight off the disease, memorizing how to fight it off incase it encounters the disease in the future.
7
Q
What are antibiotics, and how do they fight infections?
A
medications used to treat infections caused by bacteria. They work by either killing bacteria or restrain their growth, allowing the body’s immune system to more effectively fight the infection.
8
Q
What are GMO’S , and how are they used in agriculture?
A
are plants or animals that have been changed to improve certain traits. In agriculture, GMOs are often used to help crops grow better, be more resistant to pests, or withstand harsh environmental conditions like drought.
9
Q
What is bioremediation, and how does it help the environment?
A
when living organisms, like bacteria, fungi, or plants, are used to clean up and remove pollutants from the environment. These organisms break down harmful substances like oil, chemicals, or heavy metals into less harmful or harmless forms.
10
Q
What does “species” mean in the context of biological classification?
A
Are organisms that are able to mate with their own and have functioning fertile offspring.
11
Q
Define “speciation” and explain how it occurs.
A
Is the evolution of two or more species from one ancestral species
It can happen due to:
-Reproductive isolations: groups that were once considered the same become so different they can no longer mate with each other
12
Q
What is “adaptive radiation” and how does it contribute to biodiversity?
A
organisms diversify rapidly from ancestral species into many new forms.
-Contributes to biodiversity by increasing the number of different kinds of organisms in the ecosystem.
13
Q
What is “mass extinction” and how can it impact evolutionary patterns?
A
Is a wide spread and rapid decrease in the biodiversity on Earth.
-Can dramatically change evolutionary patterns by wiping out a large number of species, which opens up new opportunities for the remaining species.
14
Q
Define “natural selection” and explain how it drives evolution
A
organisms that are better adapted to their environment tend to survive and produce more offspring. Over time, organisms with better traits become more common in a population.
15
Q
What is “coevolution” and can you give an example of two species that have coevolved?
A
Is when two or more species influence each other’s evolution over time.
Ex) Bees and flowers, Cheetahs and Gazelles
16
Q
What is “genetic drift” and how does it lead to changes in a population?
A
It changes the frequency of genes in a small population over time, there is a chance of disappearance of particular genes as individuals die or do not reproduce.
17
Q
What is “decent with modification” and how does it contribute to the evolution of species?
A
Refers to how species change over time. contributes to the evolution of species by allowing them to adapt to their environment, helping them survive and reproduce more.
18
Q
How does “adaptation” help an organism survive in its environment?
A
Is a heritable trait that helps the survival of an organism in its present environment.
19
Q
Define “fitness” in the context of evolutionary biology.
A
Is the result of adaptation and the struggle for existence.
20
Q
What is a “prezygotic barrier” and how does it prevent speciation?
A
Is something that stops two organisms from mating. It prevents speciation by keeping different species from mixing their genes, which would lead to a new species forming.
21
Q
what is “postzygotic barrier” and what role does it play in reproductive isolation?
A
Refers to factors that prevent successful reproduction after fertilization has occurred. Helps with reproductive isolation as it stops the development of new species (stops species from mating, becoming separate species).
22
Q
How does “temporal isolation” prevent species from interbreeding?
A
prevents species from mating because they breed at different times. These differences can be time of day, season or even different years.
23
Q
How does “geographical isolation” contribute to speciation?
A
Occurs when a group of organisms is physically separated from the rest of their species by a barrier like a mountain, river, or ocean. Because they can’t interbreed with each other, they evolve independently over time (creates a separation in the species, making different ones).
24
Q
What is a “theory” in scientific terms, and how does I differ from a hypothesis?
A
Is a well-tested and widely accepted explanation of how something works in nature, based on a lot of evidence and research. A theory is a well-supported explanation while a hypothesis is an idea that is being investigated.
25
What is the difference between "gradualism" and "punctuated equilibrium" in the context of evolution.
Gradualism: change that happens more gradually. Change is slow, constant, and consistent.
Punctuated Equilibrium: Change comes in spurts. The species changes very rapidly over a few generations, then settles down again to a period of little change.
26
What is "artificial selection" and how is it different from natural selection?
Is when humans intentionally breed plants or animals to emphasize certain traits. Artificial selection is controlled by humans, while natural selection happens naturally in nature.
27
What does "abiogenesis" mean?
“Life from non-life” (basic chemicals)
28
What does "biogenesis" mean?
“Life from life.”
29
Which scientist used a meat experiment to disprove spontaneous generation?
Francesco Redi
30
Which scientist proved the existence if microorganisms?
Anton van Leeuwenhoek
31
Which scientists proposed the theory of natural selection (adaptive radiation)?
Charles Darwin.
32
Which scientist said that organisms change change because of an inner need to change (inheritance of acquired characteristics)?
Jean-Baptiste Lamarck
33
Give an example of an adaptation that increases an organisms survival.
Thick white fur to help keep polar bears warm and camouflaged.
34
What results in a change in a population due to chance?
mutation
35
Name one species unique to the Galapagos island.
marine iguanas
36
What was the main difference between finches on different Galapagos island.
size and shape of their beaks
37
Name 3 selective pressures that affect natural selection.
Competition
-Pollution
-Change in climate
38
What is "allopatric speciation"
When a population of organisms becomes separated or isolated from their main group.
39
What is "simpatric speciation" (speciation within the same geographic area)?
when new species form from a single population in the same geographic area, without being physically separated.
40
What is an example of pre zygotic barrier?
One example of a pre-zygotic barrier is temporal isolation. In temporal isolation, two species may live in the same habitat, but they reproduce at different times of the day, season, or year.
41
What is an example of post zygotic barrier?
An example is hybrid sterility, which can occur when two different species mate, producing a hybrid offspring that is sterile and cannot reproduce.
42
What type of isolation is caused by mating rituals?
Behavioural isolation
43
What type of isolation is caused by breeding at different times?
Temporal isolation
44
What type of isolation is caused by physical barriers like mountains or rivers?
Geographic and habitat isolation
45
What is an example of two species evolving in tandem?
pollinators and the flowers
hummingbirds and tubular flowers.
46
True or False: A human arm and a bat wing are analogous structures.
False, they are homologous.
47
True or False: A butterfly wing and a bat wing are analogous.
True
48
What is the difference between "homologous structures" and "analogous structures"
Homologous- Similar structure, different function
Analogous- Different structure, similar function
49
What is LUCA, and why is it important in evolutionary studies?
Stands for last universal common ancestor. Is important in evolutionary studies because it helps scientists understand how life on Earth evolved.
50
List the 3 main steps in the process of natural selection.
1. Struggle for existence
2. Survival of the Fittest
3. Descent With Modification
51
Analogous structures are an example of which type of evolution?
Convergent evolution
52
Homologous structures are an example of which type of evolution?
divergent evolution
53
What is the human tailbone an example of in evolutionary terms?
vestigial structure
54
What is the most common ancestor of four-limed animals?
A fish called tetrapod
55
What is the field of study called that focuses on the distribution of life over geographical areas?
Biogeography
56
What is the name of Darwin's famous book, published in 1859.
On the Origin of Species
57
Which protein do scientist often use to compare DNA similarities between species?
Hemoglobin
58
Give an example of humans using artificial selection.
dog breeding
59
What is the study of embryos in evolutionary biology called?
evo-devo (short for evolutionary developmental biology)
60
What is one structure all vertebrate embryos seem to share during early development?
tailbone
61
What can happen when HOX genes are mutated in an organism?
mutations in HOX genes can cause serious developmental problems, leading to birth defects or abnormal growth patterns in animals, including humans.
62
What is the relationship between antibiotics and bacteria in terms of evolution?
Antibiotics kill bacteria: Antibiotics are designed to target and kill harmful bacteria or stop them from growing, helping to treat infections.
Bacteria evolve to survive: Over time, some bacteria can develop resistance to antibiotics.
Survival of the fittest: When bacteria are exposed to antibiotics, those that have developed resistance are more likely to survive and reproduce.
Antibiotic resistance: As a result, over time, the number of bacteria that can resist certain antibiotics increases.
63
Red and green beetles are in the grass. Which beetle is most likely to survive, and why?
-Green beetles are more likely to survive because they are able to camouflage in the grass.
64
Where do scientist believe LUCA lived?
Hydrothermal vents
65
What does "spontaneous generation" refer to, and why was it disproved?
was the idea that living things could suddenly appear from non-living matter. It was disproved due to many science experiments including Pasteur’s famous experiment with a special curved-neck flask proved that microorganisms wouldn’t grow in broth unless air with germs could reach it, showing that life comes from existing life, not from non-living materials.
66
What is Cell Theory, and who contributed to its development?
-All living organisms are composed of one or more cells.
-Basic unit of life.
-Cells arise from pre-existing cells.
-The key contributor was Robert Hooke
67
What does the term "concentration gradient" mean in context of cellular transport?
the difference in the concentration of a substance (like molecules or ions) between two areas. In the context of cellular transport, it describes how a substance is more concentrated in one area (such as inside or outside a cell) compared to another.
68
Describe the structure of phospholipids and their role in the cell membrane.
form the basic structure of the cell membrane, acting as a barrier and regulating the movement of substances into and out of the cell. (a molecule with two fatty acids and a phosphate group attached to a glycerol backbone.)
69
What are the differences between unicellular and multicellular organisms?
Unicellular: An organism that only consist of one cell.
Multicellular: An organism that consists of more than one cell.
70
What happens when a system reaches equilibrium in terms of concentration gradients?
Concentrations of solute and solvent are equal on both sides of the membrane.
71
What is the difference between sexual and asexual reproduction?
Sexual reproduction:
-involves two parents and the fusion of gametes.
-produces offspring that are genetically unique and increases genetic variation within a species.
Asexual reproduction:
-involves only one parent.
-occurs without a fusion of gametes and produces offspring that are all genetically identical to the parent.
72
Define passive transport, and explain how it differs from active transport.
Passive transport:
DOES NOT require energy
-high to low concentration
Active transport:
Requires ATP energy.
-low to high concentration
73
What is diffusion, and how does it move substances across a membrane?
Diffusion is the process where particles move from an area where they are highly concentrated to an area where they are less concentrated.
74
What is osmosis, and why is it important for maintaining cellular functions?
is the movement of water from an area with fewer solutes to an area with more solutes. It’s important for cells because it helps maintain the right balance of water and nutrients.
75
What are the key differences between prokaryotic and eukaryotic cells?
Prokaryotic: Are the simplest and smallest cells. They don’t have a nucleus or membrane.
Eukaryotic: Have a membrane-bound nucleas and organelles.
76
How does sexual selection influence the evolution of traits in organisms?
-is a type of natural selection where certain traits become more common in a population because they help individuals attract mates and reproduce.
- leading to increased reproductive success of those who have the particular characteristics.
77
What is sexual dismorphism, and how is it related to sexual selection?
can lead to specific behaviors in males that increase their reproductive success.
-its related to sexual selection because the traits that help attract mates are passed down through generations.
78
What are organelles, and what functions do they serve within the cell?
-Are tiny structures inside cells that carry out specific functions.
ex) mitochondria: makes energy, nucleus: cells control center, ribosome: make protein, etc.
79
Explain the concept of homeostasis and its importance for organisms.
is the process that keeps the internal environment of living organisms stable, even when external conditions change. Without homeostasis, organisms wouldn’t be able to adapt to different conditions.
80
Describe the difference between animal cells and plant cells in the terms of structure and function.
Animal cells:
The building blocks that make up all living organisms in the animal kingdom.
-Have lysosomes
-Small vacuole
Plant cells:
Building blocks of all plants.
-Have cell wall that provides structure.
-Have chloroplasts for photosynthesis.
-Large vacuole.
81
What is exocytosis, and how does it facilitate the transport of materials out of the cell?
Exiting the cell.
1. Materials are packaged
2.Vesicles move to the cell membrane
3. Fusion and release
82
How do dichotomous keys help classify organisms?
It’s like a step-by-step guide that helps you figure out which group an organism belongs to, based on traits like size, color, shape, or features.
83
What role do plant cells play in photosynthesis and what organelle is involved?
plant cells play a key role in photosynthesis, which is the process where plants make their own food. The main organelle involved is the chloroplast.
84
What is endocytosis, and how do cells use this process to take in materials?
Entering the cell.
This allows the cell to bring in substances like nutrients, fluids, or even particles that are too large to pass through the cell membrane directly.
85
How is taxonomy used to classify organisms, and what are its major categories?
is the science of arranging living organisms into groups based on their shared characteristics.
Categories include:
-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species
86
What is the function of carbohydrates in living organisms?
Are an important source of energy. They provide support for cells and communication between cells
87
What are lipids, and what role do they play in the cell membrane and energy storage?
Are a group of molecules that include fats, oils, waxes, and some steroids. Lipids help keep the cell membrane flexible while also controlling what enters and leaves the cell, as well as providing long-term energy storage.
88
How do nucleic acids like DNA and RNA contribute to cellular functions?
DNA store the genetic information.
RNA helps read and carry out the instructions which is needed to make proteins and other important cellular processes.
89
Define the six kingdoms of life and provide an example organism for each.
-Bacteria: E.coli
-Archaea: Methanogens
-Protista: Amoeba
-Plantae: Oak tree
-Fungi: Mushrooms
-Animalia: Lion
90
What is the role of peptidoglycan in prokaryotic cell walls?
Its main role is to give the cell shape and provide strength, helping it maintain its structure and resist pressure from the inside.
91
What is the function of chitin in some organisms?
-a complex carbohydrate
-fungal cell wall
-a natural building block for support and protection
92
How does the binomial nomenclature system help scientists classify organisms?
-is the two name system using genus and species name to help classify organisms.
93
What is a selectively permeable membrane, and how does it regulate the flow of materials?
It only lets certain things pass through into the cell while blocking others. It decides what can enter or leave based on size, charge, or whether the substance is needed.
94
What is the difference between isotonic, hypotonic, and hypertonic solutions in terms of osmosis?
Hypotonic Solution: Concentration of solutes are higher inside the cell than outside the cell. Water moves into the cell and solutes move out of the cell. Cell will swell.
Isotonic Solution: Solute concentrations are equal inside and outside of the cell. No movement of water or solutes.
Hypertonic Solution: Concentration of solutes is lower inside the cell than outside the cell.
Water moves out of the cell and solutes move into the cell. Cell will shrivel and die.
95
How does facilitated diffusion differ from simple diffusion?
Simple diffusion: This happens when small molecules move from an area of higher concentration to an area of lower concentration without any help.
Facilitated diffusion: This is when larger molecules need help to move across the membrane.
96
Describe the process of phagocytosis and its role in immune responses.
is a process where certain cells in your immune system "eat" harmful particles, like bacteria or dead cells, to protect the body.
97
What is pinocytosis, and how do cells use it to take in fluids and small molecules?
is a process used by cells to take in fluids and small molecules from their surroundings. The cell's outer membrane forms small pockets that pinch off to create tiny bubbles or vesicles. These pockets allows the cell to absorb important nutrients or maintain its internal balance
98
What is ATP and why is it crucial for cellular energy.
It is energy and without it cells wouldn't have the energy to do essential activities, making it crucial for life.
99
How do cells use cellular respiration to produce ATP, and where does this process occur?
-Is the process where organisms use oxygen to break down food molecules to get chemical energy for cell functions. Takes place in the mitochondria.
100
What is the difference between autotrophs and heterotrophs in terns if energy acquisitions?
Autotrophs make their own food using energy from sunlight (photosynthesis) or chemicals (chemosynthesis).
Heterotrophs get their energy by eating other organisms.
101
How does photosynthesis in plant cells contribute to the energy needs of the organism?
Using sunlight, carbon dioxide (from the air), and water (from the soil), plants produce sugar (glucose) and oxygen. It provides energy for growth, repair, and all the plant’s activities.
102
What is chemosynthesis, and how does it differ from photosynthesis in terms of energy production?
Organisms use oxygen to break down food molecules to get chemical energy for cell functions. The main difference between chemosynthesis and photosynthesis is the source of energy. In photosynthesis, plants use sunlight to make food, while in chemosynthesis, organisms use chemicals from their environment.
103
What does meiosis contribute to genetic diversity in sexually reproducing organisms?
It make each offspring genetically different from both its parents and its siblings, adding to the diversity of traits in a population.
104
What is the purpose of mitosis, and how does it differ from meiosis?
Is a process where a single cell divides into two identical daughter cells.
-Mitosis produces two identical “daughter” cells from a single “parent” cell, whereas meiosis produces cells that are genetically unique from the parent.
105
Describe the process of thermoregulation and how does it differ from meiosis.
Is the process where living organisms maintain a stable internal body temperature despite changes in the external environment.Meiosis, on the other hand, is a type of cell division that occurs in reproductive cells.
106
What is the fluid mosaic model of the cell membrane, and how does it explain the structure of the membrane?
Describes membranes as a fluid combination of phospholipids, cholesterol, and proteins.
107
What are extremophiles and where can they be found?
Organisms that thrive in physically or geochemically extreme conditions that are dangerous to most life on Earth.
Halophiles – Organisms that thrive in high salt concentrations
Acidophiles – Organisms that thrive under highly acidic conditions
Thermophiles – Organisms that thrive at relatively high temperatures, between 41 and 122°C
108
How do flagella and cilia contribute to the movement of certain cells or organisms?
These structures help the cell or organism move, either by moving itself forward (like a swimmer) or by moving something around it (like clearing debris).
(Cilia are short in size and are present in large number in the cell. Flagella are longer in size and are few per cell)
109
What is the role of cellulose in plant cell walls, and how does it provide structural support?
Is a tough, fibrous substance that forms the main part of the plant cell walls. Allows plants to stand upright and grow tall, also helps protect the plant from injury and water loss.
110
What are the different types of asexual reproduction, and how do they differ from one another?
Binary Fission: One organism splits into two identical organisms.
Budding: A small part of the parent grows into a new organism.
Fragmentation: The parent breaks into pieces, and each piece can grow into a new organism.
Vegetative Propagation: A plant grows new plants from parts of itself like a leaf, stem, or root.
Parthenogenesis: the production of an embryo from a female gamete without any genetic contribution from a male gamete
Sporogenesis: one-celled reproductive body that can grow into a new organism without uniting with another cell.
Spore Formation: The parent produces spores, tiny single-celled organisms. (grow into new organisms)
111
What is heredity, and does it influence traits?
Describes how some traits are passed on from the parents to the offspring.
112
Define genetics and explain its role in inheritance.
The process where a parent passes certain genes onto their children. (helps explain why children may look like their parents and why certain traits run in families.)
113
What is a gene, and how do alleles affect genetic expression?
Are small sections of DNA that are coded for specific traits. Alleles determines how those traits appear.
114
Explain the difference between dominant and recessive traits.
Dominant- one allele will cover over the other allele for a particular trait and will be passed onto the offspring (trait that shows).
Recessive- alleles only show up when two copies of the recessive allele are inherited.
115
What does it mean to be heterozygous for a gene?
two alleles in the gene are different
116
What does the Law of Segregation describe in relation to alleles?
Parents pass only one of their two gene copies to their children, chosen at random. So each parent contributes one allele for a specific trait. (ex. eye colour)
117
State the Law of Dominance and provide an example.
When different alleles for a characteristic are inherited, only one will be expressed (the dominant one).
Ex) red flower and white flower are mixed and the offspring is a red flower
118
What is the difference between homozygous and heterozygous genotypes?
Heterozygous: two alleles in the gene are different
Homozygous: two alleles in the gene are the same
119
Explain the Law of Independent Assortment
When alleles of two or more different genes get sorted into gametes independently of one another.
120
Compare and contrast phenotype and genotype.
Genotype- the instructions coded in your DNA that you inherited from your parents.
Phenotype- This is the actual result of those instructions—how your traits show up physically or behaviorally. Ex) includes things like your eye color, height, or even how you respond to certain environments.
121
What is incomplete dominance, and how does it affect traits?
When one allele is not completely dominant over another.
EX) crossing a red flower with a white flower and ending up with a pink flower
122
Define sex linkage and give an example of a sex-linked trait.
Genes located on the X chromosome are inherited with that X.
ex) If a male inherits the allele for color blindness on his single X chromosome, he will be colorblind because there is no second X chromosome to mask the defective allele. A female must inherit the allele for color blindness on both of her X chromosomes (one from each parent) to be colorblind. If she inherits the allele from only one parent, she will be a carrier and typically not show symptoms, but she can pass the allele on to her offspring.
123
What are multiple alleles, and how do they differ from simple Mendelian inheritance?
3 or more allele of the same gene that code for a single trait. ( there are many “options” for a gene, but you only get one of them.) Mendelian inheritance involves two alleles per gene, while multiple alleles involves 3 or more alleles.
124
What is codominance and provide an example.
When both alleles show up in the offspring.
Ex) a black rooster and white chicken mate. They produce all offspring that are black and white spotted.
125
What is gene flow, and how does it affect genetic diversity?
Is the process of genes being transferred from one population to another. This increases genetic diversity because it can make a population more adaptable to changes in the environment, like disease or climate shifts.
126
Define genetic drift and give an example of how it can occur.
It changes the frequency of genes (or alleles) in a small population over time, there is a chance of disappearance of particular genes as individuals die or do not reproduce. An example can be a natural disaster occurrence makes a certain gene more useless (beak shape) , and that trait slowly disappears and animals die and don't reproduce.
127
How does meiosis contribute to genetic variation?
Meiosis ensures that each individual has a unique set of genes, contributing to the variety seen in populations.
128
What are chromosomal abnormalities, and how can they affect an organism?
Numerical abnormalities- are whole chromosomes either missing or extra to the normal pair.
Structural abnormalities- are when part of an individual chromosome is missing, extra, switched to another chromosome, or turned upside down.
Can interfere with the body's ability to work correctly and may lead to health problems, growth issues, or developmental delays,
129
What is a karyotype, and what information does it provide?
A picture of a person’s chromosomes.
It helps doctors see chromosome numbers, chromosome structures, sex chromosome, and genetic disorders.
130
How do DNA and RNA differ in structure and function?
-RNA has ribose sugar while DNA has deoxyribose sugar.
-RNA has uracil while DNA has thymine.
-RNA is single stranded while DNA is double stranded.
-RNA can leave the nucleus (carries the message) while DNA can’t leave the nucleus.
131
What is Gregory Mendel credited with discovering in the field of genetics?
Credited for the Mendelian Inheritance which is the simple inheritance of dominant and recessive genes.
132
What is Johannes Friedrich Miescher known for in the study of DNA?
credited with the discovery of nucleic acids which is now referred to as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
133
How did Erwin Chargaff contribute to our understanding of DNA structure?
found that in DNA, the ratios of adenine (A) to thymine (T) and guanine (G) to cytosine (C) are equal.
134
What was Rosalind Franklin's role in the discovery of the DNA double helix?
revealed the double helix of DNA by using a technique called X-ray crystallography to capture detailed images of DNA
135
What did James Watson and Francis Crick contribute to the study of genetics?
Their joined work led to the identification of the structure of DNA.
136
What is the difference between the P1, F1, and F2 generations?
P1 Generation (parental generation)- The first set of parents in a breeding experiment. These are the original individuals with specific traits that are being studied.
F1 Generation (First Filial Generation): The offspring of the P1 generation.
F2 Generation (Second Filial Generation): The offspring of the F1 generation.
137
What is trisonomy and how does it differ from monosomy?
Trisomy means having an extra copy of a chromosome.
Monosomy means having a missing copy of a chromosome.
138
What are examples of chromosomal abnormalities such as down syndrome and turners syndrome?
Down syndrome: When a person has an extra copy of chromosome 21.
Turner syndrome: When a female is missing or partially missing one of the two X chromosomes.
Edwards syndrome: When there is an extra chromosome 18.
Klinefelter syndrome: Happens in males who have an extra X chromosome. (XXY)
139
What is DNA composed of, and what are the base pairings between nucleotides?
DNA (Deoxyribonucleic Acid) is like a twisted ladder made of:
Sugar and Phosphate Backbone: The sides of the ladder.
Nitrogenous Bases: The “rungs” of the ladder are made of four chemical bases:
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
The bases pair up in a specific way:
Adenine (A) pairs with Thymine (T).
Cytosine (C) pairs with Guanine (G).
140
Describe the process of DNA replication and the roles of DNA polymerase, primate, helicase, and ligase.
DNA replication is the process by which a cell makes an exact copy of its DNA before dividing.
Helicase: Unzips the DNA strand.
Polymerase: The builder replicates the DNA to build a new strand.
Primase: The initializer that makes the primer fot the polymerase.
Ligase: Helps glue DNA fragments together.
141
What is RNA, and how does MRNA differ from tRNA?
RNA: is a molecule in living things that helps turn instructions in DNA into proteins, which do most of the work in cells. You can think of RNA as a messenger or helper.
mRNA: messenger RNA
tRNA: transfer RNA (transfers message)
142
What is transcription, and where does it occur in the cell?
The DNA nucleotide sequence being copied from DNA to mRNA and occurs in the cells nucleus.
143
What is translation, and how does it relation to protein synthesis?
-Message from mRNA is translated to a specific protein.
-tRNA looks for a specific amino acid in the cytoplasm that it can take to the ribosome to join with a certain codon, finding other amino acids to form protein.
-tRNA then is free to find more of the same amino acid to make protein.
144
What are point mutations, and how do they affect the genetic code?
A change in the DNA sequence of a living organism.
Types:
Duplication- addition of gene
Deletion- loss of gene
Inversion- rotation of a gorup of genes within one chromosome
Translocation- Exchange of parts between chromosomes of different pairs
145
Explain frameshift mutations, and how do they affect the genetic code.
Point Mutation- is a small change in the DNA sequence where a single building block (called a nucleotide) is altered. DNA is like a long string of letters (A, T, C, G), and a point mutation changes just one of those letters.
Frameshift- is like a typo in the genetic instructions of a cell. It happens when DNA loses or gains one or more “letters” (bases), which shifts the way the cell reads the genetic code.
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What is epigenetic, and how does it affect gene expression?
It involves changes that affect how your genes work without changing the actual DNA sequence. For example, diet, stress, physical activity, and exposure to toxins. This can impact health, traits, and even the likelihood of developing certain conditions.
