Science Midterms

Question 1

What characteristics do all living things share?

Answer 1

Living things are made of basic units called cells, are based on a universal genetic code, obtain and use materials and energy, grow and develop, reproduce, respond to their environment, maintain a stable internal environment, and change over time.

Question 2

What is a hypothesis?

Answer 2

A possible explanation for a set of observations or possible answer to a scientific question.

Question 3

Why are atoms neutral?

Answer 3

They have equal numbers of protons and electrons.

Question 4

solute

Answer 4

substance that is dissolved in a solution

Question 5

solution

Answer 5

type of mixture in which all the components are evenly distributed

Question 6

solvent

Answer 6

dissolving substance in a solution

Question 7

What is a theory?

Answer 7

In science, the word theory applies to a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations.

Question 8

What is the ecological significance of interdependence?

Answer 8

Ecology is the scientific study of interactions among organisms and between organisms and their physical environment.
Interactions within the biosphere produce a web of interdependence between organisms and the environments in which they live.

Question 9

Explain how the biogeochemical cycling of oxygen, carbon, nitrogen, and hydrogen are important to living systems.

Answer 9

These biogeochemical cycles are important to living systems because without them, nothing could survive. We need oxygen, we breathe our carbon, and we couldn’t breathe without nitrogen or hydrogen either.

Question 10

What is the difference between human and natural disturbances to climax communities?

Answer 10

Secondary succession in healthy ecosystems following natural disturbances often reproduces the original climax community. Ecosystems may or may not recover from extensive human-cause disturbances.

Question 11

Why are estuaries so important?

Answer 11

Estuaries serve as spawning and nursery grounds for many ecologically and commercially important fish and shellfish species including bluefish, striped bass, shrimp, and crabs.

Question 12

immigration

Answer 12

movement of individuals into an area occupied by an existing population

Question 13

emigration

Answer 13

movement of individuals out of an area

Question 14

density-dependent limiting factor

Answer 14

limiting factor that depends on population density

Question 15

density-independent limiting factor

Answer 15

limiting factor that affects all populations in similar ways, regardless of the population density

Question 16

Why is biodiversity important?

Answer 16

Biodiversity’s benefits to society include contributions to medicine and agriculture, and the provision of ecosystem good and services.

Question 17

deforestation

Answer 17

destruction of forests

Question 18

global warming

Answer 18

increase in the average temperatures on Earth

Question 19

prokaryote

Answer 19

unicellular organism that lacks a nucleus so does not separate their genetic material

Question 20

eukaryote

Answer 20

organism whose cells contain a nucleus which separates the genetic material from the rest of the cell

Question 21

What would happen if a cell’s membrane became impermeable?

Answer 21

Nutrients and other beneficial particles would not be able to get into the cell and it would probably die.

Question 22

Give the equation for photosynthesis in words and symbols.

Answer 22

6CO(2)+6H(2)O (light)—> C(6)H(12)O(6)+6O(2)

carbon dioxide + water (light)—-> sugars and oxygen

Question 23

Explain ATP input and output in terms of glycolysis.

Answer 23

2 ATP in, 4 ATP out

Net Gain: 2 ATP

Question 24

What is the role of oxygen in electron transport?

Answer 24

It is the final electron receptor.

Question 25

sexual reproduction

Answer 25

type of reproduction in which cells from two parents unite to form the first cell of a new organism

Question 26

asexual reproduction

Answer 26

process of reproduction involving a single parent that results in offspring that are genetically identical to the parent

Question 27

How is cytokinesis in plant cells different from cytokinesis in animal cells?

Answer 27

In most animal cells, the cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts. Each part contains its own nucleus and cytoplasmic organelles.
In most plant cells, a structure known as the cell plate forms halfway between the divided nuclei. The cell plate gradually develops into cell membranes that separate the two daughter cells. A cell wall then forms in between the two new membranes, completing the process.

Question 28

How does temperature affect enzymatic action?

Answer 28

Enzymes produced by human cells generally work best at temperatures close to 37 degrees Fahrenheit, the normal temperature of the human body.

Question 29

What do the cell membrane, cell wall, nucleus, and cytoplasm do in which cells?

Answer 29

The cell membrane is made up of lipid bilayers and monitors what does in a and out of the cell. It is thin and flexible. The cell wall helps plants stand against the force of gravity and keeps harmful materials out. It is strong and dense. The nucleus stores DNA in eukaryotic cells. The cytoplasm is outside the nucleus and makes up a good amount of the cell. You are likely to find a cell wall, a cytoplasm, and a cell membrane in a prokaryotic cell. You are likely to find all four in a eukaryotic cell. You are likely to find all four in a plant cell. You are likely to find all but the cell wall in an animal cell.

Question 30

What characteristics do all living things share?

Answer 30

Living things are made up of basic units called cells, are based on a universal genetic code, obtain and use materials and energy, grow and develop, reproduce, respond to their environment, maintain a stable internal environment, and change over time.

Question 31

Name the location, charge, and mass of protons, electrons, and neutrons.

Answer 31

Protons - center of atom, positively charged, same mass as neutrons
Neutrons - center of atom, no charge, same mass as protons
Electrons - constant motion around space surrounding nucleus, negatively charged, 1/1840 the mass of a proton

Question 32

carnivore

Answer 32

organism that obtains energy by eating animals

Question 33

herbivore

Answer 33

organism that obtains energy by eating only plants

Question 34

omnivore

Answer 34

organism that obtains energy by eating both plants and animals

Question 35

scavenger

Answer 35

animal that consumes the carcasses of other animals

Question 36

Explain the stages of primary succession on land.

Answer 36

The first plants and animals that arrived have seeds, spores, or adult stages that travel over large distances. Slowly, other species are able to take hold and join the ecosystem.

Question 37

What is the difference between density-dependent and density-independent factors?

Answer 37

Density-dependent limiting factors include competition, predation, herbivory, parasitism, disease, and stress from overcrowding.
Unusual weather such as hurricanes, droughts, or floods, and natural disasters such as wildfires, can act as density-independent limiting factors.

Question 38

What are agriculture’s benefits to society and harmfulness to the environment?

Answer 38

Agriculture is helped by biodiversity by using plant breeding and genetic engineering.
However, humans alter habitats, hunt, introduce invasive species, release pollution into food webs, and contribute to climate change.

Question 39

Explain the electrons in chlorophyll.

Answer 39

As light shines, more electrons are passed to the electron transport chain from chlorophyll. The thylakoid membrane contains a system that provides new electrons to chlorophyll to replace those it has lost.

Question 40

What is the relationship between photosynthesis and cellular respiration?

Answer 40

Photosynthesis removes carbon dioxide from the atmosphere, and cellular respiration puts it back. Photosynthesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food.

Question 41

What happens in four stages of mitosis?

Answer 41

During prophase, the genetic material inside the nucleus condenses and the duplicated chromosomes become visible. Outside the nucleus, a spindle starts to form. During metaphase, the centromeres of the duplicated chromosomes line up across the center of the cell. Spindle fibers connect the the centromere of each chromosome to the two poles of the spindle. During anaphase, the chromosomes separate and move along spindle fibers to opposite ends of the cell. During telophase, the chromosomes, which were distinct and condensed, begin to spread out into a tangle of chromatin.