Year 11 ATAR Human Biology Semester One Exam

What is the scientific method?

An organized, logical approach used to solve a problem or question.

What are the key components of the scientific method?

It is a list of steps that serves as a guide for problem solving, not a fixed procedure.

What is an observation in the context of the scientific method?

Information gained through the senses.

What senses can be used for observations?

Sight, hearing, smell, touch, and taste.

What is an inference?

An explanation of an observation.

What is a hypothesis?

A positive statement based on an observation that can be tested with an experiment.

What are the characteristics of a good hypothesis?

It must be definite, short, contain one single idea, and link two variables.

What is an independent variable?

The variable that is deliberately manipulated to test its effect.

What is a dependent variable?

The measured variable that forms the result of an experiment.

What are controlled variables?

All other variables that might affect the results.

What are uncontrolled variables?

Variables that are overlooked by the experimenter or impossible to control.

What is a placebo?

An inactive substance that looks like the real medication, used in medical treatments.

What is the purpose of a blind experiment?

To ensure that both control and experimental groups do not know if they are taking the active or inactive substance.

What is a double-blind experiment?

Neither the researcher nor the participants know who is taking the active or inactive substance.

What is validity in an experiment?

The extent to which an experiment tests what it is supposed to test.

What is reliability in an experiment?

The extent to which an experiment gives the same result each time it is performed.

How can reliability be increased in an experiment?

By reducing experimental error.

What is qualitative data?

Data that describes qualities or characteristics.

What is quantitative data?

Data that can be measured and expressed numerically.

What is biological variance?

Differences between individuals that can affect experimental results.

Why is sample size important in experiments?

It reduces the influence of biological variation and allows for the calculation of averages.

What are anomalous results?

Outliers that are well beyond the range of the rest of the measurements.

How should results be recorded during an experiment?

Results need to be clearly recorded at the time of observation into a suitable results table.

What is the purpose of graphing data in biology?

Graphing displays the data logically, making it easier to see relationships between the independent and dependent variables.

What are trends in the context of graphing?

Trends are descriptions of the general direction of a line or curve of a graph.

What is the primary difference between a bar graph and a line graph?

Line graphs show changes over time, while bar graphs are best used for comparing different groups or significant changes.

When are line graphs most useful?

Line graphs are useful for showing changes over time, such as weather patterns or CO2 production during exercise.

When should bar graphs be used?

Bar graphs should be used when comparing different groups or when there are significant changes over time.

What are some common measurements of data in biology?

Common measurements include averages/means, ratios, rates, percentages, and percentage change.

How is percentage change calculated?

Percentage change is calculated using the formula: (New value - Original value) / Original value × 100.

What two key parts should a conclusion include?

A conclusion should outline whether the hypothesis was supported and reference the experimental data in support.

What is the role of the independent variable in an experiment?

The independent variable is the one being tested or manipulated, while the dependent variable is measured.

What is the difference between a control group and an experimental group?

The experimental group contains the independent variable, while the control group is identical except for the absence of the independent variable.

How does sample size affect experimental reliability?

A larger sample size means more data, resulting in less skew and greater confidence in the results.

What is selection bias?

Selection bias is the introduction of an uncontrolled variable that can affect the outcome, often due to intentional or unintentional selection of participants.

How can random sampling reduce selection bias?

Random sampling minimizes the effect of bias by ensuring that both experimental and control groups are selected without bias.

What is reliability in the context of experiments?

Reliability refers to the consistency of results, which can be improved through repetition, using averages, and larger sample sizes.

What is validity in experimental design?

Validity refers to how well an experiment measures what it is intended to measure, which can be improved by controlling variables and using randomization.

What is the significance of the SA:V ratio in cells?

A smaller cell has a greater surface area to volume ratio, making it better equipped to transport substances and function efficiently.

What does the cell theory state?

The cell theory states that all organisms are made of cells, which are the basic unit of life, and that cells arise from pre-existing cells.

What are the main components of a human cell?

Human cells consist of a cell membrane, cytoplasm, organelles, cytoskeleton, and inclusions.

What is a trend in data analysis?

A trend is a general direction in which data points move over time, indicating patterns or relationships.

What is the psychosomatic effect?

The psychosomatic effect refers to changes in physical health that are influenced by emotional or psychological factors.

What is replication in scientific experiments?

Replication refers to repeating an experiment to verify results and ensure reliability.

What is biological variation?

Biological variation refers to differences among individuals within a species, which can affect experimental outcomes.

What is the function of the cell membrane?

It separates the cell contents from the environment, protects the cell, and controls what goes in and out.

What is the cytoplasm?

The jelly-like or watery material inside the cell that fills the space between the nucleus and the cell membrane.

What is cytosol?

The liquid part of the cytoplasm, consisting of 75% to 90% water with dissolved substances.

What is the role of the nucleus in a cell?

It contains DNA, controls the structure and function of the cell, and allows large molecules to enter and leave through nuclear pores.

What is the function of ribosomes?

They join amino acids together to make proteins and can be free in the cytoplasm or attached to the endoplasmic reticulum.

What are the two types of endoplasmic reticulum (ER)?

Rough ER (with ribosomes attached) and Smooth ER (without ribosomes).

What is the function of the Golgi body?

To modify proteins and package them for secretion from the cell.

How do proteins produced at ribosomes reach the Golgi body?

They pass through the channels of the endoplasmic reticulum.

What is the function of lysosomes?

They contain digestive enzymes that break down large molecules and worn-out organelles.

What is the structure and function of mitochondria?

A double-membraned structure where most chemical reactions of cellular respiration occur, with an inner membrane that increases surface area.

What are cilia and flagella?

Cilia are short and numerous projections, while flagella are longer and fewer; both can move the cell or substances over the cell surface.

What is the cytoskeleton?

A framework of protein fibers that gives the cell its shape and assists in cell movement.

What are microtubules and microfilaments?

Microtubules are hollow rods that keep organelles in place, while microfilaments move materials around the cytoplasm or the whole cell.

What are inclusions in a cell?

Chemical substances not part of the cell structure, such as hemoglobin and melanin, found in the cytoplasm.

What is the fluid mosaic model of the cell membrane?

It describes the membrane as fluid due to the constant movement of molecules and mosaic because it is composed of various types of molecules.

What are phospholipids?

Lipid molecules containing a phosphate group, arranged in a bilayer in the cell membrane.

What is the hydrophilic and hydrophobic nature of phospholipids?

The head is hydrophilic (water-loving) and the tail is hydrophobic (water-hating).

What types of protein molecules are found in cell membranes?

Receptor proteins, channel proteins, carrier proteins, and cell-identity markers.

What role do nuclear pores play in the nucleus?

They allow large molecules, such as messenger RNA, to enter and leave the nucleus.

What determines the type of proteins a cell can make?

The DNA contained within the nucleus.

How do lysosomes digest materials?

They join with vesicles and use digestive enzymes to break down materials for digestion or other uses.

What is the significance of the inner membrane folding in mitochondria?

It produces a large surface area for chemical reactions of cellular respiration.

What is the primary role of the endoplasmic reticulum?

To provide storage, support, synthesis, and transport within the cell.

What are the components of the 'tail' of a phospholipid molecule?

Two fatty acids that are hydrophobic and do not dissolve in water.

What substances can easily pass through the cell membrane?

Lipid soluble substances, tiny molecules like water and urea, small uncharged molecules such as oxygen and carbon dioxide.

What substances are typically impermeable to the cell membrane?

Most water soluble molecules, ions, and polar molecules.

List three functions of the cell membrane.

Acts as a physical barrier, regulates the passage of materials, is sensitive to changes.

How does the cell membrane support the cell?

It helps maintain the cell's structure and provides a binding site for enzymes.

What are the three main transport mechanisms across the cell membrane?

Diffusion, facilitated diffusion, and active transport.

What is diffusion?

A passive process resulting from the random movement of ions and molecules, where particles spread out to become evenly distributed.

What is osmosis?

The movement of water molecules across a semi-permeable membrane from a region of high water concentration to a region of low water concentration.

What is the concentration gradient?

The difference in concentration that brings about diffusion, where molecules move from high concentration to low concentration.

What type of diffusion involves the movement of water?

Osmosis.

What is the role of carrier proteins in transport?

They help transport larger molecules like glucose and amino acids that cannot fit through the membrane.

What is the difference between active and passive transport?

Active transport requires energy in the form of ATP, while passive transport does not.

What is facilitated diffusion?

A process that requires special proteins in the cell membrane and can be either passive or active.

What happens to the rate of diffusion as the concentration gradient increases?

The rate of diffusion increases with a greater difference in concentration.

What is osmotic pressure?

The pressure created by the higher concentration of solute on one side of a membrane.

Why can alcohol and steroids easily enter cells?

Because they are fat soluble substances that can diffuse through the lipid portions of the membrane.

What type of molecules must pass through protein channels to enter a cell?

Water soluble molecules.

What is the significance of the cell membrane being semi-permeable?

It allows some molecules to pass through while restricting others.

How does the movement of water occur during osmosis?

Water moves from an area of low concentration of solute to an area of high concentration of solute.

What is the process of active transport?

A process in which materials are moved in membrane-bound sacs, requiring energy.

What is the importance of the cell membrane's sensitivity to changes?

It allows the cell to respond to environmental changes.

What are interlocking surfaces in the cell membrane responsible for?

They bind cells together, forming junctions.

How do carrier proteins function in facilitated diffusion?

Molecules bind to specific carrier proteins, which change shape to move the molecule across the membrane.

What are the characteristics of carrier-mediated transport?

Carrier-mediated transport can become saturated and is regulated by substances such as hormones.

What is active transport?

A process that requires energy (ATP) to move molecules across the membrane against their concentration gradient.

What are the two types of active transport?

Carrier-mediated active transport and vesicular transport.

What is vesicular transport?

The movement of substances within membranous sacs (vesicles) that require energy to form.

What is endocytosis?

The process of taking in solids or liquids by enclosing them in a membrane that pinches off to form a vesicle.

What are the two types of endocytosis?

Pinocytosis (liquid uptake) and phagocytosis (solid uptake).

What is exocytosis?

The process where contents of vesicles are expelled from the cell.

What factors affect the rate of diffusion?

Size of particles, concentration gradient, and temperature.

How does the size of particles affect diffusion?

Larger molecules diffuse more slowly than smaller molecules.