biology Flashcards
1
Q
What is the Krebs cycle also known as?
A
The citric acid cycle or TCA cycle
The Krebs cycle is named after Hans Krebs, who identified it in 1937.
2
Q
Where does the Krebs cycle take place in the cell?
A
Inside the mitochondria
Mitochondria are often referred to as the power plants of the cell.
3
Q
What molecule starts the Krebs cycle?
A
Acetyl-CoA
Acetyl-CoA is derived from the breakdown of carbohydrates, fats, and proteins.
4
Q
What does Acetyl-CoA combine with to form citric acid?
A
Oxaloacetate
This reaction marks the beginning of the Krebs cycle.
5
Q
What are the main products generated during the Krebs cycle?
A
- NADH
- FADH₂
- ATP
- CO₂
NADH and FADH₂ are crucial for the electron transport chain, while ATP is the energy currency of the cell.
6
Q
What is the role of NADH and FADH₂ in the Krebs cycle?
A
They are energy-carrying molecules
These molecules play a key role in producing ATP in subsequent cellular processes.
7
Q
What is ATP and why is it important?
A
Adenosine Triphosphate; it is the main energy currency of the cell
ATP is essential for various cellular functions including movement and metabolism.
8
Q
What waste product is produced during the Krebs cycle?
A
Carbon Dioxide (CO₂)
CO₂ is expelled from the body when we breathe out.
9
Q
What happens to oxaloacetate at the end of the Krebs cycle?
A
It is regenerated
This regeneration allows the cycle to continue with new Acetyl-CoA.
10
Q
Why is the Krebs cycle important for the body?
A
- It helps produce energy from food
- It provides building blocks for important molecules
- It removes waste (CO₂)
The cycle is essential for cellular respiration and overall metabolism.
11
Q
Light microscope and SEM uses
A
LM: Light & Lenses
SEM: Electron Beam
12
Q
Light microscope sees?
A
live specimen, bacteria
13
Q
SEM can sees
A
dead specimen, tiny details on surfaces
14
Q
Color of light microscope
A
all colors; colored
15
Q
color of SEM
A
black and white
16
Q
What is a Prokaryotic Cell?
A
A prokaryotic cell is a very simple, tiny cell that does not have a nucleus. These cells are the building blocks of bacteria and other small organisms.
17
Q
What is a key feature of prokaryotic cells regarding their nucleus?
A
Prokaryotic cells do not have a nucleus. Their DNA just floats around inside the cell.
18
Q
How do prokaryotic cells compare in size to other types of cells?
A
They are much smaller than other types of cells and don’t have many parts inside—just the essentials to stay alive.
19
Q
What structure do most prokaryotic cells have for shape and protection?
A
Most prokaryotic cells have a cell wall to give them shape and protection.
Think of it like a shell or a jacket around the cell.
20
Q
What is a flagellum in prokaryotic cells?
A
Some prokaryotic cells have a tail-like structure called a flagellum to help them swim around.
21
Q
Can you give examples of prokaryotic cells?
A
Examples include bacteria (like the kind that live in your gut or cause infections) and archaea (tiny organisms that live in extreme places like hot springs).
22
Q
What is the Cell Membrane?
A
It protects the cell and controls what goes in and out.
Think of this as the wall and door of a house.
23
Q
What is Cytoplasm?
A
It is the jelly-like fluid inside the cell that holds everything in place and helps things move around.
24
Q
What is the Nucleus?
A
It is the control center of the cell that contains DNA, which is like the instruction manual for the cell.
Only found in Eukaryotic Cells.
25
What is Mitochondria?
Known as the powerhouse of the cell because it makes energy, helping the cell do everything it needs to stay alive.
26
What are Ribosomes?
Tiny factories that make proteins, which are needed for the cell to grow and repair itself.
27
What is the Endoplasmic Reticulum (ER)?
A transportation system inside the cell. Smooth ER makes fats, while Rough ER has ribosomes that help make proteins.
28
What is the Golgi Apparatus?
It packages and ships proteins to different parts of the cell, like a post office.
29
What are Lysosomes?
Like a garbage disposal, it breaks down waste and unwanted materials.
## Footnote
Only found in Animal Cells.
30
What is the Cell Wall?
A strong outer layer that gives plant cells their shape and protection.
## Footnote
Only found in Plant Cells & Bacteria.
31
What are Chloroplasts?
These help plants make food using sunlight (photosynthesis).
## Footnote
Only found in Plant Cells.
32
What do plant cells have that animal cells do not?
Plant cells have a cell wall, chloroplasts, and a large vacuole.
33
Why do plant cells have a cell wall, chloroplasts, and a large vacuole?
They need structure and make their own food.
34
What are two features of animal cells?
Animal cells are more flexible and have lysosomes for digestion and centrioles for cell division.
35
What is the extracellular matrix (ECM)?
The ECM is like the glue and scaffolding that holds cells together in tissues. It’s a network of proteins and other molecules outside the cells that gives them support, structure, and communication.
36
What is ECM made of?
ECM is made of collagen, elastin, proteoglycans, fibronectin, and laminin.
37
What is collagen?
Collagen is a strong protein that provides structure (like steel in buildings).
38
What is elastin?
Elastin makes tissues stretchy (like rubber bands).
39
What are proteoglycans?
Proteoglycans trap water to keep tissues hydrated and cushioned.
40
What do fibronectin and laminin do?
Fibronectin and laminin help cells stick to the ECM and communicate.
41
Where do we find ECM?
ECM is found in the skin, bones and cartilage, and blood vessels.
42
What role does ECM play in the skin?
In the skin, ECM keeps it firm and elastic.
43
What role does ECM play in bones and cartilage?
In bones and cartilage, ECM provides strength and flexibility.
44
What role does ECM play in blood vessels?
In blood vessels, ECM keeps them strong but flexible.
45
What is the first stage of the cell cycle?
G1 (Growth 1 phase) – The cell grows bigger and gets ready for work. It also checks if everything is okay to move forward.
46
What happens during the S phase of the cell cycle?
S (Synthesis phase) – The cell makes a copy of its DNA so that both new cells will have the same genetic information.
47
What occurs in the G2 phase of the cell cycle?
G2 (Growth 2 phase) – The cell grows some more and prepares all the tools it needs for division.
48
What is the final stage of the cell cycle?
M (Mitosis phase) – The cell splits into two identical cells.
49
What are cyclins?
Cyclins are special proteins that appear and disappear at different stages of the cell cycle. They act like traffic lights, giving the signal to go forward.
50
What are CDKs?
CDKs (Cyclin-Dependent Kinases) are enzymes that work like drivers. They only function when paired with the right cyclin.
51
What happens when cyclins and CDKs pair up?
When the right cyclin and CDK pair up, they push the cell forward to the next phase of the cycle.
52
What occurs if there is something wrong during the cell cycle?
If something is wrong (like damaged DNA), the cell pauses to avoid making mistakes.
53
What happens to cyclins and CDKs after the cell cycle is complete?
When the job is done, cyclins disappear, and CDKs stop working until the next cycle.
54
What are the consequences of not having cyclins and CDKs?
Without cyclins and CDKs, cells might grow uncontrollably, leading to problems like cancer.
55
What role do cyclins and CDKs play in the cell cycle?
They help keep the cell cycle smooth and organized.
56
What is DNA packing?
DNA packing is how long strands of DNA fit inside the tiny nucleus of a cell.
57
How long is DNA in each human cell?
DNA is about 2 meters long in each human cell.
58
What are histones?
Histones are small protein balls that DNA wraps around.
59
What do nucleosomes look like?
Nucleosomes look like beads on a string.
60
What is chromatin?
Chromatin is a more compact form of DNA made from coiled nucleosomes.
61
What are chromosomes?
Chromosomes are tightly packed DNA structures that form when the cell is ready to divide.
62
Why is DNA packing important?
DNA packing saves space, protects DNA, and controls gene activity.
63
How does DNA packing save space?
It fits DNA inside the tiny nucleus.
64
How does DNA packing protect DNA?
It keeps DNA from getting tangled or damaged.
65
How does DNA packing control gene activity?
Loosely packed DNA can be read for making proteins, while tightly packed DNA stays inactive.
66
What are chromosomes?
They are tightly packed DNA that hold genes, which are like little recipes for making proteins and controlling how your body works.
## Footnote
Each chromosome is made of DNA wrapped around proteins (histones) to keep it organized.
67
How many chromosomes do humans have?
Humans have 46 chromosomes (23 pairs) in almost every cell.
## Footnote
We get half from our mother (23) and half from our father (23).
68
Why are chromosomes important?
They store genetic information, pass traits to offspring, and help cells divide properly.
## Footnote
They ensure each new cell gets the right instructions.
69
What are the two main types of cell division?
Mitosis and Meiosis.
70
What is mitosis?
Mitosis makes exact copies of cells.
71
Where does mitosis occur?
In most body cells like skin, muscle, and bone.
72
What is the purpose of mitosis?
Helps with growth, repair, and replacing old cells.
73
How many cells are produced in mitosis?
One cell splits into two identical cells with the same DNA.
74
What is meiosis?
Meiosis makes special cells for reproduction (sperm and egg).
75
Where does meiosis occur?
Only in reproductive organs.
76
What is the DNA content of new cells produced by meiosis?
Each new cell has half the usual DNA.
77
How many cells are produced in meiosis?
One cell splits into four unique cells.
78
What is the first step of mitosis?
Prophase – DNA coils into chromosomes, and the cell prepares to divide.
79
What happens during metaphase?
Chromosomes line up in the middle of the cell.
80
What occurs in anaphase?
The chromosomes are pulled apart to opposite sides.
81
What happens during telophase?
Two new nuclei form, and the cell starts to split.
82
What is cytokinesis?
The cell fully splits into two.
83
cells releasing signals that act on themselves, affecting their own like gusto iregulate ang sarili so she sends signal to herself
autocrine signaling
84
cells release signal molecules that act locally on NEARBY cells
paracrine signaling
85
involves release of hormones into the bloodstream, cell targets a distant cell through the bloodstream
endocrine signaling
86
through gap junctions and tight junctions; allows direct passage of molecules between adjacent cells
-magkadikit na cell
Juxtracrine signaling
87
from an area of higher concentration to lower concentration
PASSIVE TRANSPORT
88
simple movement of molecules from high concentration to low concentration until everything is balanced.
Diffusion
89
only for water. Water moves from where there's more water to where there's less water through a semi-permeable membrane.
Osmosis
90
Some molecules are too big or charged, so they need help from special proteins to pass through the cell membrane.
Facilitated diffusion
91
- requires energy; form of ATP
- low to high concentration
ACTIVE TRANSPORT
92
The cell engulfs large particles like bacteria or food.
Example: White blood cells swallow bacteria to protect the body.
Phagocytosis
93
The cell takes in liquids and small molecules by forming tiny vesicles.
Example: Cells absorbing nutrients from their surroundings.
Pinocytosis
94
The cell specifically selects certain molecules using receptors before bringing them in.
Example: Cells taking in cholesterol for use in the body.
Receptor-Mediated Endocytosis
95
refers to how a solution affects a cell’s water movement through osmosis. It depends on the concentration of solutes (like salt or sugar) inside and outside the cell.
Tonicity
96
The solution outside the cell has less solute and more water than inside the cell.
Water enters the cell, causing it to swell and possibly burst (lysis).
Example: A red blood cell in pure water swells up.
Hypotonic Solution (Water Moves Into the Cell
97
The solution outside the cell has more solute and less water than inside the cell.
Water exits the cell, causing it to shrink and shrivel (crenation in animal cells, plasmolysis in plant cells).
Example: A red blood cell in salty water shrinks.
Hypertonic Solution (Water Leaves the Cell
98
The solution outside and inside the cell has the same solute concentration.
Water moves in and out at the same rate, so the cell stays the same size.
Example: Red blood cells in IV fluids (which are isotonic to blood).
Isotonic Solution (Water Moves In & Out Equally
99
Why Is Tonicity Important?
Cells must maintain the right balance of water and solutes to survive. Too much water? They burst. Too little water? They shrink.
100
3 stages of aerobic respiration
glycolysis
krebs cycle
oxidative phosphorylation
101
the first step of breaking down sugar (glucose) to make energy. . It happens in all cells and doesn’t need oxygen!
Glycolysis
102
What do you get glucose from?
You get glucose from food like rice, bread, or fruits.
103
What happens to glucose in the cell?
The glucose (6-carbon molecule) is broken into two smaller molecules called pyruvate (3-carbons each).
104
What is produced during glycolysis?
A small amount of ATP (the cell’s energy) is produced.
105
What carries electrons to the next stage of respiration?
Special molecules called NADH carry these electrons to the next stage.
106
What are the key results of glycolysis?
✅ 2 Pyruvate molecules (go to the next step of respiration).
✅ 2 ATP molecules (energy for the cell).
✅ 2 NADH molecules (help make more energy later).
107
What is the transition reaction?
The transition reaction is a small but important step between glycolysis and the Krebs cycle in cellular respiration.
108
What does the transition reaction prepare?
It prepares pyruvate so the cell can extract more energy!
109
Where do pyruvate molecules move after glycolysis?
The 2 pyruvate molecules move into the mitochondria.
110
What happens to carbon during the transition reaction?
One carbon is removed from each pyruvate and released as carbon dioxide (CO₂).
111
What is produced when NAD+ grabs electrons?
NAD+ becomes NADH, which carries energy to the next step.
112
What is formed when the remaining 2-carbon molecule attaches to Coenzyme A?
Acetyl-CoA is formed, which enters the Krebs cycle.
113
final step in cellular respiration, where your cells make a lot of energy (ATP)!
Oxidative phosphorylation
114
location of oxidative phosphorylation
inner mitochondrial membrane
115
process of oxidative phosphorylation
- NADH and FADH2 donate electrons to the ETC
- protons H+ are pumped into the intermembrane space, creating a proton gradient. ATP is produced
- oxygen acts as the final electron acceptor, forming water
116
how cells make energy without using oxygen. It happens when your body needs energy fast, like during intense exercise or in places with no oxygen
Anaerobic respiration
117
process of anaerobic respiration
- Glucose is Broken Down – Just like in aerobic respiration, glucose is the fuel.
- No Oxygen is Used – Instead of going through the full process (Krebs cycle & oxidative phosphorylation), the cell takes a shortcut.
- Less ATP is Made – Anaerobic respiration makes only 2 ATP molecules, compared to 38 ATP in aerobic respiration.
- Byproducts Are Created – Since oxygen isn’t there to clean up, waste products build up.
118
types of anaerobic respiration
Lactic Acid Fermentation (in humans & animals)
Alcohol Fermentation (in yeast & bacteria)
119
Happens in muscles when you exercise hard.
Produces lactic acid, which causes muscle cramps & fatigue.
Example: Sprinting or lifting heavy weights.
Lactic Acid Fermentation
120
Used to make bread, beer, and wine.
Produces alcohol (ethanol) and carbon dioxide (CO₂).
Alcohol Fermentation (in yeast & bacteria)
121
segments of DNA that encode
instructions for building and maintaining an
organism
Genes
122
a different version of a gene that
can result in different variations of a
particular trait
Alleles
123
considered the father of
modern genetics, as he conducted
groundbreaking experiments with pea plants
in the 19th century, leading to the discovery
of the basic principles of inheritance
Gregor Mendel
124
expressed in an
organism's phenotype when presen
Dominant alleles
125
are only expressed when
two copies are present.
recessive alleles
126
refers to the genetic makeup of an
organism
Genotype
127
refers to the observable
characteristics resulting from the interaction
of genes and the environment.
Phenotype
128
DNA is made up of tiny building blocks called nucleotides. Each nucleotide has three parts:
Sugar (deoxyribose)
Phosphate group
Nitrogen bases ATCG
129
Start Codon (methione)
AUG
130
Stop Codons
UAA, UAG, UGA
131
alterations or
changes in the DNA sequence of an
organism's genome
Genetic mutations
132
Mutation) – One letter (base) in DNA is switched with another.
Point Mutation
133
The letter changes, but the protein stays the same.
Silent Mutation
134
The letter change causes a different amino acid to be made, which may affect the protein
Missense Mutation
135
The letter change creates a STOP codon too early, making the protein shorter and often useless.
Nonsense Mutation
136
happens when a DNA letter (base) is added or deleted, which shifts the entire reading frame of the genetic code.
frameshift mutation
137
a big change in DNA that affects whole sections of a chromosome, not just a single letter (like point or frameshift mutations). These mutations can delete, add, or rearrange large parts of a chromosome, leading to major effects.
chromosomal mutation
138
A big chunk of a chromosome is lost, which means important genes are missing.
Example: Cri-du-chat syndrome (caused by a deletion on chromosome 5).
Deletion
139
A section of a chromosome is copied twice, leading to extra genes.
Example: Some genetic disorders happen because of too many copies of a gene.
Duplication
140
A piece of a chromosome flips and reattaches in the wrong direction.
Example: Can lead to fertility problems or no effect at all.
Inversion
141
A section of one chromosome breaks off and attaches to a different chromosome.
Example: Some cancers (like leukemia) are caused by translocations.
Translocation
142
a random change in DNA that happens naturally, without any outside influence like radiation or chemicals. These mutations occur by accident when cells copy their DNA.
spontaneous mutation
143
a change in DNA that happens because of external factors like radiation, chemicals, or viruses
Induced Mutations
144
foundational concept in molecular biology
The central dogma of genetics was proposed
by Francis Crick in 1958
145
outlines the unidirectional flow of genetic
information from DNA to RNA to protein.
The central dogma of genetics
146
the process of
copying DNA to produce identical
daughter DNA molecules.
DNA replication
147
An enzyme called _______ unzips the double-stranded DNA, breaking the hydrogen bonds between base pairs (A-T, G-C).
helicase
148
An enzyme called _______ adds new bases to match the original strand.
A pairs with T, G pairs with C (base-pairing rule).
DNA polymerase
149
