2B1 Living vs Nonliving Things

Question 1

Define:

cell theory

Answer 1

• Everything living is made of cells.
• The smallest structural component of everything living is the cell.
• Existing living cells create new cells.

Question 2

Who coined the term ‘cell’ and described cells in detail in 1665?

Answer 2

Robert Hooke

Hooke named them cells because when he examined a piece of cork under the microscope he noticed little structures that reminded him of the living quarters of monks- also known as cells.

Question 3

What did Matthias Schleiden discover about plants and cells in 1838?

Answer 3

That plants are comprised of cells.

Question 4

After hearing about Schleiden’s discoveries with plant cells, what did Theodor Schwann discover in 1839 about animals and cells?

Answer 4

That animals are comprised of cells.

Question 5

What was Rudolf Virchow’s contribution to classical cell theory?

Answer 5

He proposed the third and final tenet that all living cells must come from other living cells.

Question 6

Who discovered and described unicellular bacteria and protists?

Answer 6

Antonie van Leeuwenhoek

Question 7

Who studied cellular division in frog embryos in the 1850s?

Answer 7

Robert Remak

Question 8

Which scientist identified chromosomes and mitosis in salamander cells in the 1880s?

Answer 8

Walther Flemming

Question 9

Who described how cells pass down chromosomes (DNA) during division?

Answer 9

August Weismann

Question 10

What did the cell theory put an end to?

Answer 10

The debate about spontaneous generation.

The cell theory rejected the idea that cells appeared ‘out of thin air’.

Question 11

What additional concepts does modern cell theory add to classical cell theory?

Answer 11

• Chemical energy flows within cells. (metabolism)
• Genetic material is transferred to new cells during cellular division. (DNA)
• All cells are chemically and structurally similar.

Question 12

What process converts energy from sunlight into food in plants?

Answer 12

Photosynthesis

Question 13

What are autotrophs?

Answer 13

Organisms that can produce their own food.

Auto means self.

Question 14

What is the chemical equation for photosynthesis?

Answer 14

6CO₂ + 6H₂O yields C₆H₁₂O₆ + 6O₂

CO₂= carbon dioxide
H₂O= water
C₆H₁₂O₆= glucose
O₂= oxygen

Question 15

What is the main function of chlorophyll in photosynthesis?

Answer 15

Absorbing specific wavelengths of light energy.

Chlorophyll absorbs red and blue wavelengths of light to fuel photosynthesis.

Question 16

What wavelengths of visible light does chlorophyll mostly absorb?

Answer 16

• Blue
• Red

Green wavelengths are reflected.

Question 17

How do electrons in chlorophyll behave when they absorb light energy?

Answer 17

They jump to a high energy level, or excited state.

Question 18

Where does chlorophyll exist in plant cells?

Answer 18

Within the thylakoid membranes of plant chloroplasts.

Question 19

Fill in the blanks:

Photosynthesis is essentially the reverse of ________ ________.

Answer 19

cellular respiration

Question 20

What are heterotrophs?

Answer 20

Organisms that must eat other organisms to get energy and nutrition.

Hetero means other.

Examples: insect, birds, humans

Question 21

What is the purpose of an energy pyramid?

Answer 21

To show how energy is transferred within the trophic levels.

Question 22

What percentage of energy is transferred from one trophic level to the next?

Answer 22

10%

The other 90% of energy is lost as heat produced by metabolic processes.

Question 23

What is a living organism?

Answer 23

Anything that exhibits all of the characteristics of life.

Examples: Humans, fungi, algae, trees, animals, bacteria, protozoa, insects.

Question 24

What is the basic unit of organization in living organisms?

Answer 24

cells

Living organisms can either be unicellular or multicellular.

Question 25

What are the common **characteristics of living organisms**?

Answer 25

* Cellular organization * Reproduction * Growth and development * Regulation * Respond to stimuli * Use and obtain nutrition * Excretion of waste

Question 26

What is **cellular organization** in living organisms?

Answer 26

It ranges from atoms and molecules to cells, tissues, organs, organ systems, and the entire organism.

Question 27

What are the **two types of cells** that comprise living organisms?

Answer 27

* **Eukaryotic cells**: organelles are surrounded by a membrane. * **Prokaryotic cells**: organelles are not surrounded by a membrane.

Question 28

What is **reproduction** in living organisms?

Answer 28

The process of **producing new individuals**. ## Footnote Reproduction can be sexual (requiring a partner), or asexual (not requiring a partner).

Question 29

What are the **two ways** in which offspring are produced in living organisms?

Answer 29

* Sexual reproduction * Asexual reproduction

Question 30

**Differentiate** between sexual and asexual reproduction.

Answer 30

* **Sexual reproduction** involves the fusion of gametes, resulting in genetic diversity. * **Asexual reproduction** involves a single parent and produces genetically identical offspring.

Question 31

What are **gametes**?

Answer 31

Specialized **sex cells** produced by each parent for sexual reproduction. ## Footnote Male gamete: sperm Female gamete: ova

Question 32

How do living organisms **obtain energy**?

Answer 32

From metabolism of food and cellular respiration. ## Footnote The sun is the ultimate source of energy in an ecosystem. Producers convert sunlight to a usable form that is able to be consumed by other living organisms.

Question 33

What is the **response to stimuli** in living organisms?

Answer 33

The ability to **detect and respond** to physical or chemical changes in the internal or external environment. ## Footnote Example: Venus flytrap snapping shut quickly when a fly lands on it.

Question 34

What is **regulation** in living organisms?

Answer 34

The ability to **regulate internal functions** in response to external stimuli.

Question 35

What is the term for the specific characteristics that living organisms develop to **thrive in their environment**?

Answer 35

Adaptations

Question 36

What is the term for the process by which living organisms obtain energy by **breaking down food**?

Answer 36

Cellular respiration

Question 37

What is the term for the change from a **small size to a larger size** in living organisms?

Answer 37

Growth

Question 38

What is the term for the **change in features and characteristics** throughout the life of an organism?

Answer 38

Development

Question 39

# Define: spermatogenesis

Answer 39

The process by which **sperm cells develop in the testes** through a sequence of mitotic and meiotic divisions, resulting in four haploid sperm.

Question 40

# Define: oogenesis

Answer 40

The process of creating **female gametes** (ova).

Question 41

# Define: zygote

Answer 41

The **diploid cell** formed when a sperm **fertilizes an egg**, marking the first stage of embryonic development.

Question 42

What is **cleavage** in the context of animal development?

Answer 42

The process by which the zygote rapidly divides without growing to become multicellular.

Question 43

What are the **three major body axes** that the zygote must establish after fertilization?

Answer 43

* Anteroposterior axis (head to tail) * Dorsoventral axis (back to belly) * Transverse axis (left to right)

Question 44

What are the **three primary germ layers** in animal development?

Answer 44

* Ectoderm * Mesoderm * Endoderm

Question 45

What is the process of the **formation of organs** in the embryo called?

Answer 45

Organogenesis

Question 46

What is **homeostasis**?

Answer 46

Regulation of an organism's internal environment.

Question 47

What is **evolutionary adaptation**?

Answer 47

Living things are descendants of their ancestors and adapt to their environments over long periods of time.

Question 48

Which **body systems** are involved in homeostasis?

Answer 48

**All** body systems.

Question 49

What are the **three main systems** of homeostasis in body systems?

Answer 49

* Thermoregulation * Osmoregulation * Chemical regulation

Question 50

# Define: thermoregulation

Answer 50

The process of regulating body **temperature**.

Question 51

# Define: osmoregulation

Answer 51

The maintenance of the body's **salt and water balance** in homeostasis.

Question 52

# Define: chemical regulation

Answer 52

The process of maintaining **homeostasis of chemicals** in the body.

Question 53

What are the **main components** of body systems for maintaining homeostasis?

Answer 53

* Sensor/Receptor * Control center * Effector ## Footnote * **Sensor/Receptor**: nervous system detects a change. * **Control center**: brain determines how to respond. * **Effector**: organs carry out orders from the brain and returns the body to homeostasis. Example: The nerves in your skin sense that the environment is cold. Signals then go to your brain as the control center. Your brain then directs the blood vessels near the surface of your skin to contract so the blood will not come as close to the cool surface of your skin.

Question 54

What is the **hypothalamus** and what is its function?

Answer 54

Portion of the brain that controls the **endocrine system** and helps maintain **homeostasis** in the body.

Question 55

# Define: endocrine system

Answer 55

Body system that uses **hormones** that travel through the blood to convey messages.

Question 56

How does the hypothalamus regulate **body temperature**?

Answer 56

By processing sensory information and causing changes in effector organs, such as sweating and dilating blood vessels to release excess heat.

Question 57

What are the two main types of **feedback loops** in maintaining homeostasis?

Answer 57

* Positive feedback loops * Negative feedback loops

Question 58

What occurs in a **positive feedback loop**?

Answer 58

The product of the effector stimulates the effector and increases the product. ## Footnote Example: A woman is pregnant and nearing birth. The body releases oxytocin, leading to increased uterine contractions. As the contractions continue, more oxytocin is released leading to the continuation and amplification of labor until the baby is born. Once the baby is born the high level of oxytocin being released stops.

Question 59

What occurs in a **negative feedback loop**?

Answer 59

The original state is restored due to a response that opposes that change. ## Footnote Example: Your body senses that as you are working out the concentration of oxygen in your blood is low. In response, you begin breathing heavily and your heart beats more rapidly. Your body will continue to behave this way until you slow down your exercise and your oxygen levels return to normal. Once homeostasis has been achieved your breathing and heart rate will also return to their normal level.

Question 60

How are **blood glucose levels** controlled?

Answer 60

By the pancreas secreting insulin when levels are high and glucagon when levels are low.

Question 61

# Define: diabetes

Answer 61

A condition where **dysfunction of glucose homeostasis** causes blood glucose levels to be too high. ## Footnote Normal blood glucose levels: 100 mg/dL (fasting) and no more than 140mg/dL 2 hours after eating.