Microbial Nutrition, Ecology, and Growth Flashcards
1
Q
This is the process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities.
A
Nutrition
2
Q
These are substances that an organism must get from its environment because it cannot make them on its own.
These must be provided to an organism.
A
Essential Nutrients
3
Q
What are the 2 Categories of Essential Nutrients?
A
- Macronutrients
- Micronutrients or trace elements
4
Q
Needed in large amounts because they help build cells and provide energy.
Examples: Proteins and carbohydrates (which are crucial for growth and metabolism).
A
Macronutrients
5
Q
Needed in small amounts but still very important because they help enzymes work and keep proteins stable.
Examples: Manganese, zinc, and nickel (which help in different body functions, like digestion and immune support).
A
Micronutrients or trace elements
6
Q
Nutrients can be divided in 2 Types. What are these?
A
- Organic Nutrients
- Inorganic Nutrients
7
Q
These contain both carbon (C) and hydrogen (H) and usually come from living things.
Examples: Carbohydrates, lipids (fats), proteins, nucleic acids (DNA/RNA), and methane (CH₄).
A
Organic Nutrients
8
Q
These do not contain both carbon and hydrogen together. They come from non-living sources.
Examples: Water (H₂O), oxygen (O₂), carbon dioxide (CO₂), and minerals like magnesium sulfate and sodium phosphate.
A
Inorganic Nutrients
9
Q
The Cell is composed of 70% _______?
- The main ingredient, essential for life. It helps in chemical reactions and keeps the cell hydrated.
A
Water
10
Q
The cell is also composed of ________.
- Important for building and repairing cell structures, enzymes, and many cell functions.
A
Proteins
11
Q
Six Main Elements (96% of the Cell)
- These six elements make up most of the cell’s material.
What are these?
A
- Carbon (C) – Forms the backbone of all organic molecules.
- Hydrogen (H) – Found in water and organic compounds, helps in energy transfer.
- Oxygen (O) – Needed for respiration and making water.
- Phosphorus (P) – Important for DNA, RNA, and energy storage (ATP).
- Sulfur (S) – Found in some proteins and helps in their structure.
- Nitrogen (N) – Found in proteins and nucleic acids (DNA & RNA).
REMEMBER THE ACRONYM CHOPS-N
12
Q
Organisms get carbon in two main ways. What do you call these organisms?
A
Heterotrophs and Autotrophs
13
Q
They depend on other living things for carbon.
- They get carbon from organic molecules like proteins, carbohydrates, lipids, and nucleic acids.
- Example: Humans, animals, and fungi (we eat food to get carbon).
A
Heterotrophs
Note: “Hunters” (Get carbon from others).
14
Q
They make their own food using CO₂ (an inorganic gas).
- They do not need other living things for carbon.
- Example: Plants, algae, and some bacteria (they use photosynthesis to convert CO₂ into energy).
A
Autotrophs
Note: “Self-feeders” (Make their own carbon-based food).
15
Q
These are organic compounds that an organism cannot make on its own because it lacks the necessary genes or metabolism to produce them.
🔹 Since the organism cannot synthesize them, it must get them from its environment.
A
Growth Factors
Easy way to remember:
- If the body can’t make it, it must take it! 😊
16
Q
Give 2 Examples of Growth Factors.
A
- Essential amino acids – Needed to build proteins (e.g., lysine, tryptophan).
- Vitamins – Help enzymes function properly (e.g., Vitamin B12, Vitamin C).
👉 Think of growth factors like “must-have ingredients” in a recipe. If you don’t have them, you can’t complete the dish! 😊
17
Q
Organisms are classified based on how they obtain:
- ____________ (for building cell structures)
- ____________ (to power their functions)
A
- Carbon
- Energy
18
Q
Organisms get energy in two main ways. What do you call these organisms?
A
Chemotrophs and Phototrophs
19
Q
Get energy from chemical compounds (e.g., bacteria that break down food or chemicals).
A
Chemotrophs
20
Q
Get energy from light (photosynthesis) (e.g., plants, algae).
A
Phototrophs
21
Q
FAMILIARIZE ONLY!
Nutritional Types of Organisms
A
Easy way to remember:
- Hetero = Gets carbon from others
- Auto = Makes its own carbon
- Chemo = Gets energy from chemicals
- Photo = Gets energy from light 🌞
22
Q
Autotrophs make their own food using Inorganic sources, but they can get energy in different ways:
There are 3. What are these?
A
- Photoautotrophs (Use Light for Energy)
- Chemoautotrophs (Use Chemicals for Energy)
- Methanogens
23
Q
There are 2 under Photoautotrophs on which how they use Light for Energy. What are these?
A
Oxygenic photosynthesis and Anoxygenic photosynthesis
24
Q
Uses sunlight and produces oxygen.
Example: Plants, algae, and cyanobacteria
A
Oxygenic photosynthesis
25
**Uses sunlight but does not produce oxygen.**
Example: Purple and green sulfur bacteria
Anoxygenic photosynthesis
26
Also called **lithoautotrophs** (meaning "rock-eating"), they survive on **inorganic substances** like sulfur or iron.
Example: Certain bacteria and archaea in deep-sea vents
**Chemoautotrophs** (Use Chemicals for Energy)
27
A kind of **chemoautotroph** that produces **methane gas (CH₄)** instead of oxygen.
Lives in **anaerobic (no oxygen) environments**, like swamps or inside animal guts.
Methanogens
28
Heterotrophs must **obtain both carbon and energy** from organic sources (living or dead organisms).
Majority of Heterotrophs are ________?
* **They get energy from chemical compounds and use aerobic respiration (like humans).**
Chemoheterotrophs
29
What are the **Two Categories of Heterotrophs**?
1. **Saprobes** (Decomposers)
2. **Parasites**
30
Live on **dead** organic material
* Feed on decaying plants, animals, and waste.
Example: **Fungi, bacteria, and molds**
**Saprobes** (Decomposers)
31
There are **2 classified under saprobes** because they typically live as free-living organisms, feeding on dead organic material. However, in certain conditions, they can switch to parasitic behavior and infect living hosts.
What are these?
**Opportunistic pathogen** and **Facultative parasite**
32
A microorganism that **does not usually cause disease** but can become harmful if the host's immune system is weak.
ADD INFO ONLY!
Example: **Candida (yeast)** – Normally harmless but can cause infections in people with weak immunity.
Opportunistic pathogen
33
An organism that **can live freely in the environment** but **can also infect a host** when the opportunity arises.
Example: **Fungi or certain bacteria** that live in soil but can infect humans if they enter the body.
Facultative Parasite
34
**"What is the difference between Opportunistic Pathogens and Facultative parasites?"**
* **Opportunistic pathogens** cause disease only in weak hosts.
* **Facultative parasites** can choose to live freely or parasitize a host.
35
Unlike saprobes, which feed on dead material, _________ **steal nutrients from living organisms and may cause harm. It also depends on a living host for survival and nutrients.**
Parasites
36
There are **2 Types of Parasites**. What are these?
**Pathogens** and **Obligate Parasites**
37
**Parasites that cause disease in their host.**
Example: Bacteria (Mycobacterium tuberculosis), viruses (HIV), and protozoa (Plasmodium – malaria).
Pathogens
38
**Can only survive inside a host and cannot live freely in the environment.**
Example: **Viruses** (they need host cells to reproduce), some bacteria (**Chlamydia**), and protozoa (**Plasmodium** – malaria-causing parasite).
Obligate Parasites
39
**"What is the difference between Pathogens and Obligate Parasites?"**
* **Pathogens** = Disease-causing parasites 🦠
* **Obligate parasites** = Must live inside a host (no other option!) 🏠
40
**If an organism is degrading large organic molecules to get both carbon and energy, it would be best described as a**
A. Photoheterotroph
B. Photoautotroph
C. Chemoheterotroph
D. Chemoautotroph
**C. Chemoheterotroph**
Note:
* The organism is **degrading large organic molecules**, meaning it gets **carbon from organic sources** → Heterotroph
* It is using **chemical breakdown** to get energy, not light → **Chemo**
41
It **does not require energy**. This is where substances move from **high to low** concentration (down the gradient).
Passive Transport
42
**Passive Transport has 3 types** based on how the chemicals move across the cell membrane. What are these?
* **Diffusion** – Movement of molecules (e.g., oxygen, carbon dioxide).
* **Osmosis** – Diffusion of **water** across a membrane.
* **Facilitated Diffusion** – Uses a **carrier protein** to help transport molecules (e.g., glucose transport).
43
This **Requires Energy**. In this process, molecules move substances against the concentration gradient **(low to high)**.
Active Transport
44
**Active Transport has 3 types** based on how the chemicals move across the cell membrane. What are these?
1. **Active Transport** – Uses **energy (ATP) and carrier proteins** (e.g., sodium-potassium pump).
2. **Group Translocation** – The transported molecule is **chemically modified** during transport (e.g., glucose phosphorylation).
3. **Bulk Transport** – Moves large particles using **vesicles**.
* **Endocytosis** – Engulfing substances **into** the cell (e.g., phagocytosis for solids, pinocytosis for liquids).
* **Exocytosis** – Releasing substances **out** of the cell.
45
This is bringing substances **into the cell** through a **vesicle or phagosome**.
Endocytosis
46
There are **two types of Endocytosis**. What are these?
**Phagocytosis** and **Pinocytosis**
47
This is also called **"cell-eating"**. The cell **engulfs large particles**, such as bacteria or debris.
* Forms a **phagosome** (a vesicle containing the ingested material).
Example: **White blood cells engulf bacteria.**
Phagocytosis
48
This is also called **"cell-drinking"**. The cell **takes in liquids** along with small dissolved molecules.
Example: **Absorption of nutrients in the intestines.**
Pinocytosis
49
**If a cell is in a concentrated glucose solution and the glucose is moving into the cell through a carrier protein, this would be an example of**
A. Diffusion
B. Facilitated Diffusion
C. Active Transport
D. Endocytosis
E. Pinocytosis
B. Facilitated Diffusion
50
The **specific environment** where a microbe lives, based on its **adaptations**.
Niche
51
Microbes live in different environments, and their **growth and survival** depend on several factors. These factors **affect their enzymes and metabolism**, which determine where they can thrive.
What are the **Environmental factors** that affect the function of metabolic enzymes?
***Give 5.***
1. Temperature
2. Oxygen requirements
3. pH
4. Osmotic pressure
5. Barometric pressure
52
Microbes have a specific **temperature range** where they can survive and grow.
What are the **3 Cardinal Temperatures**?
1. **Minimum Temperature**
2. **Maximum Temperature**
3. **Optimum Temperature**
53
The **lowest temperature** at which a microbe can still **grow and function**.
Below this, metabolism slows down, and the microbe may become **inactive** (but not necessarily die).
Minimum Temperature ❄️
54
The **highest temperature** a microbe can tolerate.
Above this, **proteins denature**, and the microbe **dies**.
Maximum Temperature 🔥
55
The **best** temperature for **fastest growth and metabolism.**
This is where **enzymes work efficiently**, allowing rapid reproduction.
Optimum Temperature 🌱
56
Microbes are classified based on the temperatures they **prefer and can survive in**:
What are the **3 Temperature Adaptation Groups**?
1. **Psychrophiles**
2. **Mesophiles**
3. **Thermophiles**
57
* Optimum Temperature: **Below 15°C**
* Can grow at: **0°C or lower**
* Found in: **Deep oceans, glaciers, refrigerators**
* Example: **Polar bacteria, algae in icy waters**
**Psychrophiles** ❄️ (Cold-Loving)
58
* Optimum Temperature: **20°C - 40°C**
* **Includes most human pathogens** because body temperature is **37°C**
* **Found in**: Soil, water, human bodies
* Example: **E. coli, Staphylococcus aureus**
**Mesophiles** 🌱 (Moderate Temperature Lovers)
59
* Optimum Temperature: **Above 45°C**
* **Found in:** Hot springs, deep-sea hydrothermal vents, compost piles
* Example: **Thermus aquaticus (used in PCR technology)**
**Thermophiles** 🔥 (Heat-Loving)
60
FAMILIARIZE ONLY!
When microbes use **oxygen** for energy, they produce harmful byproducts, including these **4**. What are these?
* **Singlet oxygen (¹O₂)** – a highly reactive form of oxygen.
* **Superoxide ion (O₂⁻)** – damages proteins and DNA.
* **Peroxide (H₂O₂)** – toxic if not broken down.
* **Hydroxyl radicals (OH⁻)** – extremely reactive and destructive to cells.
61
FAMILIARIZE ONLY!
To survive oxygen exposure, most microbes produce **neutralizing enzymes** including these 2. What are these?
* **Superoxide dismutase (SOD)** – converts superoxide ion (O₂⁻) into less harmful substances.
* **Catalase** – breaks down peroxide (H₂O₂) into water (H₂O) and oxygen (O₂), preventing damage.
62
Microbes **without these enzymes** cannot neutralize toxic oxygen byproducts. As a result, they must live in _____________ environments, such as deep soil, swamps, or the human gut, to survive.
**oxygen-free** (anaerobic)
63
Uses **oxygen** for growth and has enzymes to detoxify harmful oxygen byproducts.
Aerobe
64
**Must have oxygen** to survive and cannot grow without it.
Obligate Aerobe
65
**Prefers oxygen** but can still grow **without it** if needed.
Facultative Anaerobe
66
Needs **only a small amount** of oxygen to grow, too much can be harmful.
Microaerophile
67
**Does not use oxygen** for growth.
Anaerobe
68
**Cannot survive in oxygen** because it lacks detoxifying enzymes.
Obligate Anaerobe
69
**Does not use oxygen**, but can **tolerate** its presence.
Aerotolerant Anaerobe
70
All microbes need _____________ for metabolism, but the amount required varies.
carbon dioxide (CO₂)
71
These are microbes that **grow best in high CO₂ levels**, higher than what is normally found in the atmosphere. They are often found in the **human body** (like in the respiratory tract) and require special incubation conditions for growth.
Capnophile
72
Most microbes grow best in a **pH range of 6 to 8**, which is close to neutral.
Neutrophiles
73
Thrive in **highly acidic** environments with **low pH** (e.g., stomach acid, acidic hot springs).
Acidophiles
74
Grow in **highly alkaline** environments with **high pH** (e.g., soda lakes, alkaline soils).
Alkalinophiles
75
Most microbes live in hypotonic or isotonic conditions, where water balance is ______.
stable
76
__________ need **high salt concentrations** to grow, often found in salty environments like the ocean.
Halophiles
77
Do not require **high concentration of solute** but can tolerate it when it occurs.
Osmotolerant
78
___________ thrive in **extreme pressure** conditions, such as deep-sea environments. They rely on high pressure for survival and will **rupture** if brought to normal atmospheric pressure.
Barophiles
79
**Chlamydomonas nivalis grows on Alaskan glaciers, and it’s photosynthetic pigments give the snow a red crust. This organism would be best described as a**
A. Psychrophile
B. Alkalinophile
C. Microaerophile
D. Osmotolerant
E. Barophile
A. Psychrophile
80
Organisms **live closely** together; at least one **depends on the relationship.**
Symbiotic
81
Organisms **live independently**; their relationship is not essential for survival.
Nonsymbiotic
82
What are the **"3 Types of Symbiotic Relationships"**?
1. Mutualism
2. Commensalism
3. Parasitism
83
Both organisms **benefit** and depend on each other.
Mutualism
84
One benefits, and the other is **unharmed**.
Commensalism
85
The **parasite benefits**, but the **host is harmed**.
Parasitism
86
What are the **"2 Types of Nonsymbiotic Relationships"**?
1. Synergism
2. Antagonism
87
**Organisms cooperate and share nutrients but don’t depend on each other.**
Example:
* Lactobacillus and Streptococcus in yogurt production work together to ferment milk, but each can survive independently.
Synergism
88
**One organism inhibits or destroys another.**
Example:
* Penicillium mold produces penicillin, which kills competing bacteria like Staphylococcus aureus.
Antagonism
89
The **human body** provides a **habitat** for many microbes, known as the ________________. These microbes form different relationships:
✅ **Commensalism:** Staphylococcus epidermidis lives on the skin, gaining nutrients without harming the host.
✅ **Parasitism:** Mycobacterium tuberculosis causes tuberculosis, harming the host.
✅ **Synergism:** Lactobacillus in the gut helps digest food and benefits alongside other bacteria.
**Normal microbial flora** (or normal microbiota)
90
These are **communities of microbes** that attach to surfaces and are held together by a **sticky extracellular matrix.**
Biofilms
91
Microbes in biofilms are found in ____________ (like river rocks), **medical settings** (like catheters), and even on **human teeth** (plaque).
Natural environments
92
Microbes in biofilms **communicate and cooperate** using a process called ___________, allowing them to coordinate activities like **resisting antibiotics or sharing nutrients.**
**Quorum sensing**
93
**"Simplified Biofilm Formation & Quorum Sensing"**
1️⃣ **Attachment** – Free-swimming microbes land on a surface and stick.
2️⃣ **Matrix Formation** – They produce a sticky substance (extracellular matrix) to hold them together.
3️⃣ **Quorum Sensing Begins** – When the biofilm reaches a certain size, microbes release signaling molecules (inducers) to coordinate activities.
4️⃣ **Gene Activation** – The signals trigger genes to produce specific proteins, like enzymes.
5️⃣ **Collective Action** – Microbes work together, secreting enzymes to break down nutrients for the whole community.
🔬 Why it Matters? Biofilms make bacteria more **resistant to antibiotics** and help them **survive harsh conditions**!
94
Microbial growth happens in **two ways**. What are these?
1. Cells increase in size
2. Increase in population
95
Most bacteria multiply through _________, where a **parent cell grows, copies its DNA, and splits into two identical daughter cells**. This process allows bacteria to multiply rapidly, especially under favorable conditions.
Binary fission
96
Time required for a **complete fission cycle** is called ___________.
**Generation time** or **Doubling time**
97
Each new fission cycle **increases the population by a factor of 2** which is called as what?
Exponential growth
98
Generation times vary from ________ to __________.
minutes to days
99
**In laboratory studies, populations typically display a predictable pattern over time.**
This is called ________.
Growth curve
100
**Bacteria grow in four stages.** What are these?
1. Lag phase
2. Exponential growth phase
3. Stationary phase
4. Death phase
101
Cells **adjust to their environment**. There is **little to no** growth. It is also called as **"flat"** period of adjustment.
Lag phase
102
A period of **maximum growth** will continue as long as cells have **adequate nutrients** and a **favorable environment**.
Exponential growth phase
103
**Growth slows**; cell death equals cell reproduction which is caused by depleted nutrients and O2, excretion of organic acids and pollutants.
Stationary phase
104
**Nutrients run out**, and **cells die** at an increasing rate.
Death phase
105
METHOD OF ANALYZING POPULATION GROWTH
**Measures cloudiness (turbidity)** of a liquid culture to estimate population size. *The higher the turbidity, the larger the microbial population.* This method is **simple and indirect** but does not provide an exact count of cells.
Turbidometry
106
Determines the number of living cells by culturing them on a nutrient medium and counting the colonies that grow.
Viable Colony Count
107
Measures all cells (both living and dead) using a microscope or automated counter (e.g., Coulter counter or flow cytometer).
Direct Cell Count
