Scientific Method, Cells and Cell Metabolism

Question 1

Scientific Method Definition

Answer 1

A systematic way of researching a question and making conclusion.

Question 2

What are variables?

Answer 2

Affect the outcome of an experiment; Independent Variable (IV) is what you change in an experiment. Dependance Variable (DV) is what you measure. The Controlled Variable (CV) is what you keep the same.

Question 3

Control Group and Experimental Group

Answer 3

Control Group doesn’t receive the Independent Variable. The Experimental Group receives Independent Variable

Question 4

What is a placebo?

Answer 4

An inactive ingredient given to the control group so they cannot decipher whether they are in the experimental or control group.

Question 5

Validity

Answer 5

An experimental design that tests what it proposes to test. Validity can be applied by controlling variables and increasing sample size.

Question 6

Reliability

Answer 6

Would you get the same results again and again? Can be applied by testing and retesting and increasing sample size.

Question 7

What makes a good hypothesis?

Answer 7

A good hypothesis is usually a definite statement not a question (it is hypothesised that…), is short, has a single idea that can be tested, usually links 2 variables.

Question 8

Experimental Errors

Answer 8

Random errors are unpredictable errors that can occur in all experiments. Systematic errors occur because of the way in which an experiment is designed (e.g. measurement may be too high or too low).

Question 9

Cell Definition

Answer 9

Smallest unit of living things. Two types: plant and animal

Question 10

Cell structure

Answer 10

Cell membrane- surrounds cell and forms the outer boundary
Cytoplasm-thick fluid that fills inside of cell and holds organelles.
Organelles-structures suspended in cytoplasm that carry out particular functions
Cytosol-liquid part of cytoplasm
Cytoskeleton- internal scaffolding or protein fibres within the cytoplasm.

Question 11

Cell Membrane (plasma membrane)

Answer 11

Protects and supports the cell, controls what enters and leaves the cell, it is a phospholipid bilayer

Question 12

Nucleus

Answer 12

Controls activities in the cell, usually one per cell, contains DNA - the coded instructions for making proteins and other molecules for the cell.

Question 13

Nucleolus

Answer 13

Small, dense region in the middle of the nucleus, where ribosomes are formed.

Question 14

Cytoplasm

Answer 14

Clear fluid within cell that contains all organelles, moves materials within the cell

Question 15

Ribosomes

Answer 15

Makes proteins, may be free in cell or attached to ER.

Question 16

Golgi apparatus (Bodies)

Answer 16

Stacks of membranes that package chemical. Packaged chemicals can be moved outside of the cell or stored inside the cell.

Question 17

Endoplasmic Reticulum

Answer 17

Series of folded membranes that form sacs or tubes. Two types - smooth or rough

Question 18

Smooth ER vs Rough ER

Answer 18

Smooth ER has no ribosomes, makes lipids, detoxifies drugs. Rough ER looks rough due to ribosomes, makes proteins through ribosomes.

Question 19

Lysosomes

Answer 19

Made by golgi apparatus, full of digestive enzymes to digest unwanted particles, help white blood cells to destroy bacteria, clean up crew.

Question 20

Vacuoles

Answer 20

Store food, water, or waste materials. In plant cells, they are very large.

Question 21

Mitochondria

Answer 21

Energy producers - the “powerhouse” of the cell, convert chemical energy into useable energy. The mitochondria come from ovum

Question 22

Cytoskeleton

Answer 22

Overlapping networks of filaments and fibres that support the cell and help it maintain it’s shape. They can also help cells move.

Question 23

Centrioles

Answer 23

Help to organise the cell during cell division, they migrate to either side of the cell and help to pull it apart. Only found in animal cells.

Question 24

Flagellum

Answer 24

Extension of the cytoskeleton - allows movement, main source of transportation for cells.

Question 25

Cilia /Pili

Answer 25

Extension of the cytoskeleton, allows things to move around the cell

Question 26

What is differentiation?

Answer 26

A process by which a single cell divides repeatedly. These new cells that arise become specialised for particular function. In an adult human body there are about 75 trillion cells which specialise into 200 types of cells. This great mass of cells are arranged in a particular way that allows each one to contribute to the functioning of the whole body.

Question 27

Body organisation

Answer 27

The body is organised on five structural levels;

cell, tissues, organs, systems, organism

Question 28

List and explain the two types of cell transport

Answer 28

Active - requires energy (ATP) and Passive - does not require energy.

Question 29

What are the three transport mechanisms?

Answer 29

Diffusion - simple and osmosis,
Carrier Mediated - facilitated and active
Vesicular - endocytosis and exocytosis

Question 30

Define diffusion and osmosis

Answer 30

Diffusion -> the movement of particles so that they are distributed evenly.
Osmosis -> the diffusion of water molecules through a differentially permeable membrane.

Question 31

Define Carrier Mediated

Answer 31

Carrier Mediated is when a carrier protein transports specific ions across the plasma membrane

Question 32

Describe facilitated diffusion

Answer 32

Carrier protein which sucks in/pushes out ion and causes a change in shape. It is passive and does not require energy

Question 33

Describe active carrier mediated transport

Answer 33

Requires energy from ATP. Moves against low -> high concentration gradient. Energy is received from mitochondria from the process of cell respiration.

Question 34

Define vesicular transport

Answer 34

Vesicular Transport is the movement of substances across the cell membrane in membranous bags called vesicles [active process]

Question 35

What is endocytosis and exocytosis?

Answer 35

Endocytosis -> taking liquid or solids into the cell by vesicular transport
Exocytosis ->when the contents of a vesicle inside the cell are passed to the outside

Question 36

What is pinocytosis and phagocytosis?

Answer 36

Pinocytosis -> process in which the cell membrane folds around a droplet of water and encloses it.
Phagocytosis -> process in which cell membrane encloses around a solid particle.

Question 37

Define metabolism

Answer 37

The chemical processes that occur within a living organism in order to maintain life
(food we eat + oxygen = energy).

Question 38

Define Metabolic Rate and Basal Metabolic Rate

Answer 38

Metabolic rate -> the rate (or speed) at which metabolism occurs in a living organism.
Basal metabolic rate -> the rate at which the body uses energy while at rest to maintain vital functions such as breathing and keeping warm

Question 39

Define the two metabolic processes

Answer 39

Anabolic - small molecules built up into larger ones, requires energy, e.g. Protein Synthesis
Catabolic - reactions in which large molecules are broken down to smaller ones, releases energy, e.g. cellular respiration

Question 40

What are organic compounds?

Answer 40

Organic compounds have large molecules that always contain the element carbon e.g. carbohydrates, amino acids, proteins, lipids and nucleic acids.

Question 41

What are inorganic compounds?

Answer 41

Substances that do not contain carbon such as water, oxygen, carbon dioxide and minerals.

Question 42

Describe what carbohydrates always contain.

Answer 42

Always contain carbon, hydrogen and oxygen. There are always twice as many hydrogen atoms as oxygen.

Question 43

What are monosaccharides?

Answer 43

Simple sugars or single unit sugars e.g. glucose, fructose and galactose

Question 44

What are disaccharides?

Answer 44

Two simple sugars joined together e.g. sucrose, maltose and lactose

Question 45

What are polysaccharides?

Answer 45

Large numbers of simple sugars joined together e.g. glycogen, cellulose and starch.

Question 46

Describe proteins

Answer 46

Always contain carbon, hydrogen, oxygen and nitrogen, and often sulfur, and phosphorus.

• made up of amino acids
• the bond that forms between amino acids is called a peptide bond; two amino acids joined by a peptide bond is called a dipeptide bond
• ten or more amino acids joined is a polypeptide

Question 47

What do lipids consist of?

Answer 47

Contain carbon, hydrogen and oxygen e.g. fats, phospholipids, steroids.
Each fat molecule consists of one molecule of glycerol and one, two, or three fatty acid molecules. The type of fat stored in the body is triglyceride.

Question 48

What are nucleic acids?

Answer 48

Very large molecules containing carbon, hydrogen, oxygen, nitrogen and phosphorus.
Made up of nucleotides, each of which contains a nitrogen base, a sugar and a phosphate.

Question 49

What is RNA?

Answer 49

Ribonucleic acid; consists of a single chain of nucleotides that contain the sugar ribose.
RNA carries information from the DNA in the nucleus to parts the cell where proteins are made.

Question 50

What is DNA?

Answer 50

Deoxyribonucleic acid; consists of two chains of nucleotides that contain the sugar deoxyribose.
Genetic material in the nucleus that stores inherited information.