biology exam revision sem 1

what is an example of active transport?

endocytosis

energy avaliable for the immediate use by a cell is in the form of?

atp

as the cell grows, the surface area to volume ratio:

decreases

cancer is caused by:

uncontrolled cell reproduction

oxygen is a product of which metabolic reaction?

photosynthesis

what is DNA like in a bacterium

one singular chromosome

cellular respiration in plants is dependent on?

the production of glucose via photosynthesis

the products of aerobic respiration are

co2 and water

what cellular structures do plants and animal cell have in common

mitochondria, linear chromosomes, golgi body

state cell theory

all cells arise from pre-existing cells, all living things are made from cells, cells are designed to perform a specialized function and chemical reaction, cells vary in size: unicellular, multicellular.

using the word semi-permeable, describe the structure of the cell membrane

the cell membrane is made from a phospholipid bilayer. protein (carrier proteins) are embedded within the membrane and cholesterol particles are attached. The membrane is semi-permeable as it allows certain nutrients, waste products. etc. to enter/exit the cell (sometimes via vesicles).

list 2 major difference between plant and animal cells

1. plant cells have a cell wall (outside the cell to provide protection, shape and structure)

2. plant cells are autotrophs and therefore have chloroplasts and a larger vacuole to facilitate the process of photosynthesis. animal cells are heterotrophs and therefore don’t have chloroplasts and have much smaller bubble like vacuoles. they primarily perform aerobic respiration in the mitochondrion.

what is the function of the mitochondrion

performs aerobic respiration to provide the cell with energy.

what is the function of the rough er?

provide a site for protein synthesis.

what is the function of the smooth er?

site for lipid and carbohydrate metabolism.

what is the function of the nucleus?

controls the function of the cell. contains cell dna in the nucleolus.

what is the function of the golgi body

stores, modifies and packages proteins, lipids and carbohydrates.

what is the function of the cytoplasm

a watery substance containing dissolved substances and organelles.

what is the function of the cell membrane?

facilitates the movement of materials, ions etc. into and out of the cell.

name the process in which bacteria replicates

binary fission

describe the steps in binary fission

1. prior to binary fission the chromosome replicates.

2. in the first step of binary fission the chromatin condenses (coils).

3. they then attach to the parent membrane.

4. respectively, the cell membrane and cell wall begin to grow inwards, pinching the cytoplasm to form 2 daughter cells.

what is the worded equation for lactic acid fermentation

glucose→ lactic acid + ENERGY

explain why bacteria must excrete lactic acid as it forms

bacteria requires energy through lactic acid fermentation, yet has no use for lactic acid itself. the high levels of lactic acid produced can be toxic to the cell however high levels of energy are required.

explain why some organisms need to produce energy via anaerobic respiration instead of aerobic respiration

when there is a limitation in the oxygen available, aerobic respiration cannot be performed and therefore to receive energy the cytoplasm must perform anaerobic respiration.

what are the four steps in mitosis

prophase, metaphase, anaphase and telophase

what happens in prophase

chromosomes condense and become visible. the nuclear membrane dissolves.

what happens in metaphase

cells align at the equator and spindle fibres attach

what happens in anaphase

the cell elongates, chromosomes break into chromatids at the centromere and are pulled by spindle fibres to the ends of the cell.

what happens in telophase

the nuclear membrane reforms, the chromosomes recondense and the spindle fibre dissolve.

what is passive transport

passive transport doesn’t require energy as it moves material with the concentration gradient: high→ low.

what are types of passive transport

1. diffusion

2. osmosis

3. facilitated diffusion

what is active transport

transport that requires energy as materials are moved against the concertation gradient: low → high.

what are types of active transport

exocytosis and endocytosis (phagocytosis + pinocytosis).

list the seven processes of living things

-        Movement

-        Respiration

-        Sensitivity

-        Growth

-        Reproduction

-        Excretion

-        Nutrition

What are 2 examples of unicellular organisms?

• bacteria

• fungi

• yeasts

What are 2 examples of multicellular organisms?

 

• plants

• mushroom

• animals

What are the two basic forms of cells?

Prokaryotic and Eukaryotic.

 List 3 features of a Prokaryotic cell.

-        Small size.

-        Circular DNA.

-        Doesn’t have a nucleus.

-        Little internal organization.

-        No membrane bound organelles.

-        Single chromosomes.

-        Cell wall made pf peptidoglycan.

List 3 features of a Eukaryotic cell.

-        Larger size.

-        Linear DNA.

-        Contains a nucleus.

-        High levels of internal organization.

-        Contains membrane bound organelles.

-        Two or more chromosomes.

-        Cell wall (if there is one) is made of cellulose.

List 3 differences between a prokaryotic cell and a eukaryotic cell.

-        Prokaryotic cells have circular DNA, Eukaryotic Cells have linear DNA.

-        Prokaryotic cells don’t have a nucleus, Eukaryotic cells do have a nucleus.

-        Prokaryotic cells have no membrane bound organelles. Eukaryotic cells contain membrane bound organelles.

-        Prokaryotic is smaller in size than Eukaryotic.

-        Prokaryotic has little organization, where Eukaryotic has high.

What cell type has circular DNA?

Prokaryotic.

What does ATP stand for?

Adenosine triphosphate.

What is the structure of mitochondria?

-        Lots of folds: increases surface area, allowing a greater number of processes to occur.

-        Double membrane bound.

Which organelle performs Aerobic respiration?

Mitochondria.

What chemical allows photosynthesis to occur?

Chlorophyll A + Chlorophyll B.

How does chlorophyll allow photosynthesis to occur?

By absorbing light.

Where does photosynthesis occur?

Chloroplasts in plant cells.

What does the cell wall do?

The cell wall provides structural support and protection to the cell, maintaining its shape and preventing it from bursting.

Is the cell wall in plant or animal cells?

plant

What are 3 main differences between plant and animal cells?

1.      Presence of chloroplasts in plant cells.

2.      Vacuole size.

3. Absence of cell wall in animal cells.

What does a vacuole do?

Stores nutrients and water.

Are vacuoles the same in plant and animal cells?

Plant vacuoles are much larger, where animal vacuoles are small ‘bubbles’.

What is the structure of the ER?

A system of membranes that exists throughout the cytoplasm.

What does the rough ER do?

It is the sight of protein and membrane synthesis and transports materials within the cell.

What organelle makes the rough ER rough?

Ribosomes attach to the outside.

What organelles appear in prokaryotes?

Cell wall, Cytoplasm, Ribosomes.

What does cytoplasm do?

Gives the cell structure and hold organelles in place.

What does the nucleus do?

Manages or controls all the cell functions in a eukaryotic cell.

 What is the structure of the nucleus.

Circular and generally located centrally in animal cells and towards the edge of the cell wall in plants.

What does the cell wall do?

Helps to store large quantities of water for use in photosynthesis.

Where is DNA found in the cell?

Nucleus.

What does the golgi body do?

Packages materials to leave the cell.

What is the structure of the golgi body?

Stacks of flattened sacs made of a smooth membrane.

A

1. Increase, 2. Decrease

What does a lysosome do?

Waste disposal using enzymes.

What is the structure of a lysosome?

Small spherical organelles in the cytoplasm.

What do ribosomes do?

Site of protein synthesis.

What is the structure of ribosomes?

Small spherical organelles, free floating or attached to ER.

What is an Autotroph?

Organisms (plants and protists) that use light energy to synthesis organic molecules through photo synthesis. (creates energy)

What is a Heterotroph?

Organisms (animals) that need to feed off other organisms to provide them with organic molecules as an energy and a nutritional source. (consumes energy)

What is homeostasis?

Stable internal environment.

What is the word and chemical equation for photosynthesis?

 

Carbon dioxide + Water à Glucose + oxygen

6CO₂ + 6H₂O à C₆H₁₂O₆ + 6O₂

(light and chlorophyll over top of arrow)

What is the word and chemical equation for aerobic respiration?

Glucose + oxygen à Carbon dioxide + Water + ENERGY

C₆H₁₂O₆ + 6O₂ à6CO₂ + 6H₂O

What is the word equation for Lactic acid fermentation?

Glucose à Ethanol + Carbon dioxide + ENERGY

What is the word equation for Alcohol fermentation?

Glucose → ethanol + ENERGY

What type of transport needs energy?

Active

What type of transport does not require energy?

Passive

What phase is a cell in when not undergoing Mitosis?

Interphase

What is Diffusion?

Movement of substances from a high concentration to a low concentration until equilibrium is reached.

What is Osmosis?

The movement of water through a semi-permeable membrane from low-solute concentration to high-solute concentration until equilibrium is reached.

What is hypotonic?

Low concentration

What is hypertonic?

High concentration

What does the cell do during interphase?

Grows, Replicates DNA, prepares for cell division.

What are the phases of mitosis?

1.      Prophase

2.      Metaphase

3.      Anaphase

4. Telophase

What is diffusion?

Movement through the membrane of small substances (usually gasses) from high to low concentration that does not require energy.

What is facilitated diffusion?

Movement through protein pumps in the membrane of large substances from high to low concentration that does not require energy.

What is exocytosis?

Exocytosis is the movement of substances out of the cell from low to high concentration that requires energy.

What is endocytosis?

Endocytosis is the movement of substances into the celll from low to high concentration that requires energy.

What is phagocytosis?

Form of endocytosis that moves large substances and food.

What is pinocytosis?

Form of endocytosis that moves liquids.

Mitosis occurs in what cells?

All cells that have a cell wall, therefore all eukaryotes.

Binary fission is the reproduction of?

Prokaryotic cells.

What is the difference between mitosis and cytokinesis?

Mitosis is the division of the nucleus. Cytokinesis is the division of the cytoplasm.

What is the product of alcohol fermentation?

Ethanol + ENERGY

What is the product of lactic acid fermentation?

Lactic acid + energy

What is the equation for how cells use energy carried by ATP?

ATP → ADP + P + Energy.

List three factors that affect the rate of photosynthesis.

Availability of:

-        Sunlight

-        Water

Carbon dioxide

List three uses that cells have for energy.

-        Growth

-        Multiplication

Transport/ Movement

What is the term used to refer to all the chemical reactions that take place in a cell?

Respiration.

What are two differences between passive and active transport?

• Whether energy is required.

• Concentration gradient.